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Photocatalytic Estrogen Degradation by the Composite of Tin Oxide Fine Particles and Graphene-like Carbon Nitride
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Cite this: ACS Omega 2024, 9, 50, 49064–49070
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https://doi.org/10.1021/acsomega.4c03390
Published December 6, 2024

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Abstract

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This study investigates whether 17β-estradiol (E2), a natural estrogen and one of the endocrine-disrupting chemicals responsible for water pollution, can be oxidatively decomposed under simulated solar light using a composite of tin oxide nanoparticles and graphene-like carbon nitride (g-CN) as a photocatalyst. The composite photocatalyst was prepared by heating a mixture of urea and tin acetate. FT-IR measurements revealed that g-CN possesses structural units similar to g-C3N4, a well-studied graphite-like carbon nitride. However, unlike g-C3N4, sharp diffraction lines were not observed in the XRD diffraction pattern of g-CN, indicating lower crystallinity. Elemental analysis showed that g-CN is slightly nitrogen-rich compared to g-C3N4, and UV–vis measurements indicated that the band gap of g-CN is slightly smaller than that of g-C3N4. The presence of tin in the composite of tin oxide and g-CN was clearly confirmed by XPS, although no sharp diffraction peaks were observed in the XRD patterns, suggesting the presence of microcrystals. Furthermore, FE-SEM observations did not reveal large tin oxide crystals, although EDS mapping indicated the presence of tin oxide. It was found that the prepared tin oxide and g-CN composites function effectively as photocatalysts for degrading E2 under simulated solar light. The degradation rate constant was evaluated to be k = 3.34 (0.14) × 10–2 min–1. Peroxide ion radicals were detected in ESR measurements from the irradiated solution, suggesting that peroxide ion radicals are generated through oxygen photoreduction as the counter-reaction of the oxidative decomposition of E2.

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Introduction

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The ecological impact of endocrine disruptors (environmental hormones) present in trace amounts in rivers has been a prominent concern. (1,2) Through numerous investigations, rivers have been revealed to be contaminated with natural estrogens such as estrone (E1), 17β-estradiol (E2), estriol (E3), and synthetic estrogens like ethinyl estradiol. (3,4) These compounds can cause harmful effects such as feminization, infertility, and hermaphroditism in organisms inhabiting water bodies. Therefore, there is a strong demand to remove these estrogens for environmental purification.
Since the 1990s, quantitative experiments have been conducted to evaluate the impact of the aforementioned estrogen on aquatic life, such as fish, in rivers. (5) Among the three types of estrogens mentioned, E2 is known to have a significant physiological effect. (5) It has been pointed out that as little as 10 ng/L of E2 can cause feminization in fish. In response to this, the removal of E2 in sewage treatment has become a critical issue, leading to active research into advanced oxidation processes, including the use of ozone, in addition to the general chlorine-based oxidizing agents for E2 degradation. Detailed studies on the oxidative decomposition process of E2 have also been conducted during this time, revealing the intermediate products through which the degradation progresses.
In recent years, there has been an active effort to use photocatalysts for environmental purification. (6,7) Using energy derived from fossil fuels for environmental purification can exacerbate environmental pollution during energy generation. By contrast, combining solar energy with photocatalysts for the purification process does not cause new environmental problems.
Among the various photocatalyst materials studied for this purpose, graphite-like carbon nitride (g-C3N4) has recently gained significant attention as a metal-free photocatalyst under visible light irradiation, as it is composed of only abundant elements, easy to synthesize, and chemically stable. (8−13) The basic tectonic units to establish g-C3N4 allotropes are considered to be triazine (C3N3) and tri-s-triazine/heptazine (C6N7) rings, although the samples actually synthesized may have several polymorphs with slightly different structures (Figure S1). The history of g-C3N4 dates back to 1834 when the embryonic form of melon was first developed. (14) After Wang reported its excellent photocatalytic hydrogen generation ability, g-C3N4 gained attention as a photocatalyst. (15) Subsequently, extensive research has been conducted on the photocatalytic applications of g-C3N4. Much of this research is driven by the perspective of addressing environmental issues. (16−18)
It has recently been reported that g-C3N4/SnO2 composite can be a visible light photocatalyst capable of photocatalytic degradation of Rhodamine B. (19) Ji reported that Rhodamine B is oxidatively decomposed by the holes generated by the photoexcitation of electrons. (14) If the same mechanism can be applied to the photocatalytic degradation of environmental hormones, river purification and environmental purification can be ideally achieved. To demonstrate this, this study synthesized g-C3N4/SnO2 composites and investigated their photocatalytic activity in decomposing E2 (Figure S2), which was used as the representative form of estrogen. This research aims to develop a photocatalyst that allows for the decomposition of estrogen by solar light. The specific purpose of this experiment is to verify whether a composite of tin oxide nanoparticles and graphene-like carbon nitride can effectively decompose E2 under the irradiation of solar light. Therefore, experiments were conducted using a high concentration (0.1 mM) aqueous solution of E2, compared to the actual concentration of E2 found in rivers (on the order of several ng/L).

Experimental Section

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The g-C3N4/SnO2 composites were synthesized through a previously reported procedure. (16) It should be noted although referred to as g-C3N4 in this paper, the g-C3N4 synthesized in the present study is somewhat structurally distorted, as will be discussed in the next section. To synthesize the composite, a mixture of urea (Nacalai Tesque Inc.) and tin(II) acetate (Sigma-Aldrich Co.) was placed in a crucible and thermally treated at 550 °C for 2 h under N2 flow in an electric furnace to obtain the g-C3N4/SnO2 composite. Various weight percentages of tin(II) acetate (0, 0.3, 0.6, and 1.5 wt %) were used to prepare the mixture. The corresponding composites were abbreviated as CNSnO-0, CNSnO-0.3, CNSnO-0.6, and CNSnO-1.5. The synthesized composite samples were characterized through spectroscopic experiments such as Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). FT-IR, XRD and XPS measurements were performed using FT/IR-6300 (JASCO Co.), Rigaku Miniflex (Rigaku Co.) and PHI Quantes (ULVAC-PHI Inc.). Elemental analysis of H, C, N was done on vario EL cube (Elementar) and the N/C ratio was also evaluated using XPS. For the FT-IR measurements, a pellet was made by mixing KBr powder with the sample and then measuring by the transmission method. The XPS measurements were conducted by pressing the sample powder onto In foil. FE-SEM (EDS) and TEM measurements were carried out using a JSM-7800F (JEOL) and a JEM-Z2500 (JEOL), respectively. UV–vis measurements were performed using Shimadzu UV-1900i spectrophotometer, and analysis based on the Kubelka–Munk theory was conducted to estimate the band gap of the carbon nitride composite samples. (17) The AC impedance measurements of the sample were performed using an Autolab PGSTAT128N, and the flat band potential was estimated from the Mott–Schottky plot. We also performed nitrogen adsorption/desorption isotherm measurements on the prepared samples at 77 K using a Gemini 2375 (Shimadzu). The Brunauer–Emmett–Teller (BET) surface area values of the samples were determined from the observed N2 adsorption isotherms.
Estradiol (E2) was purchased from Nacalai Tesque Inc. A solution of 0.1 mM E2 with the CNSnO composite was stirred in the dark for 3 h to avoid causing any light-induced changes prior to the photoirradiation experiment. Subsequently, the solution was irradiated with simulated sunlight from a solar simulator (AM1.5G, 1000 W/m2). After irradiation, the solution was centrifuged to remove the composite samples, and the change in E2 concentration was examined via photoluminescence (PL) measurements. PL measurements were carried out on FP-8600 (JASCO Co.). To investigate the mechanism of CNSnO-catalyzed E2 photodegradation, Electron spin resonance (ESR) measurements using 5,5-Dimethyl-4-phenyl-1-pyrroline N-Oxide (DMPO) purchased from Tokyo Chemical Industry Co. as a radical trapping agent were carried out to detect the reduced species in the degradation process. The ESR measurements were performed using a JES-FA200 (JEOL) at an observation frequency of 9.055 GHz.

Results and Discussion

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The FT-IR spectra of the prepared CNSnO-0 and CNSnO-0.3 are shown in Figure 1. In both samples, characteristic g-C3N4 peaks are observed, including the triazine breathing mode around 810 cm–1 (marked with asterisk) and peaks corresponding to C–N and C═N stretching vibrations in the range of 1100–1600 cm–1. (20) Therefore, the synthesized samples can be inferred to possess the basic units of g-C3N4. However, XRD measurements of CNSnO-0 resulted in only a broad halo pattern (Figure S3), whereas highly crystalline g-C3N4 exhibits diffraction lines indicative of a layered structure of hexagonal network planes and regular structures within the plane (Figures S1 and S4). (21) Therefore, we hypothesize that the CNSnO composites synthesized in this study have a somewhat distorted network structure of triazine and/or tri-s-triazine units.

Figure 1

Figure 1. FT-IR spectra of (a) CNSnO-0 and (b) CNSnO-0.3.

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Furthermore, XRD diffraction patterns of CNSnO-0.3 also show only broad diffraction lines, and no diffraction lines attributable to SnO2 crystals are observed (Figure S3). However, XPS measurements confirm the clear presence of Sn (Figure 2A). (22) Therefore, it is plausible that CNSnO-0.3 contains amorphous Sn oxides or ultra fine Sn oxide crystals. Thermogravimetric (TG) measurements of CNSnO-0.3 in air revealed residual tin oxide of about 1.5 wt %. Additionally, elemental analysis revealed an N/C ratio of approximately 1.354, indicating a nitrogen-rich composition compared with g-C3N4.

Figure 2

Figure 2. (A) Sn 3d, (B) C 1s, (C) N 1s, (D) wide XPS spectra of CNSnO-0.3.

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As mentioned above, the Sn 3d peaks are clearly observed in the XPS spectrum of CNSnO-0.3 (Figure 2A), confirming the presence of Sn. Additionally, the peak energy positions (Sn 3d5/2 = 486.6, 3d3/2 = 495.0 eV) suggest that Sn is in the +4 oxidation state (Figure S5A, Table S1). However, the O 1s XPS spectrum shows a broad peak, indicating that the presence of Sn in lower oxidation states cannot be definitively ruled out (Figure S5C). The C 1s XPS spectrum of CNSnO-0.3 exhibits peaks around 284.7 and 288 eV (Figure 2B). The high-energy-side peak can be explained by C bonded with N and is consistent with the structure of g-C3N4 (Figure S1). However, the 284.7 eV peak cannot be explained by the g-C3N4 structure shown in Figure S1. This peak may be due to carbon clusters, the presence of sp3 carbon, or contaminant carbon. Changing the measurement location revealed variations in the intensity of this peak, suggesting that it is caused by some type of impurity (Figure S5B). This low-energy-side C 1s peak is often reported in studies describing the synthesis of g-C3N4.
The strong peak around 398.5 eV in the N 1s spectrum (Figure 2C) is attributed to nitrogen in the triazine structure of the g-C3N4 structural unit. The high-energy-side shoulder peak (around 400.6 eV) is attributed to nitrogen in the C–N═N–C structure, as observed in g-C3N5. (23) Taking these findings into consideration, we conclude that the synthesized CNSnO composite shares many structural similarities with g-C3N4 shown in Figure S1, but is slightly nitrogen-rich and lacks crystalline integrity (Figure 2D).
In the FE-SEM image of the CNSnO-0.3 sample (Figure S6B), sheet-like carbon nitride can be observed, but distinct crystals of tin oxide are not visible. However, as previously mentioned, tin was detected by XPS, and tin was also detected in the SEM-attached EDS (Figure S8). The specific location of Sn is difficult to determine through EDS mapping, suggesting that tin oxide is homogeneously deposited throughout the sample. TEM observations showed a sheet-like structure of CNSnO-0.3, with what appear to be Sn oxide nanoparticles dispersed on the sheet surface (Figure S7). The BET specific surface area of the CNSnO-0.3 sample, determined by N2 gas adsorption measurements, is 68.0 cm2/g (Table S2), which is relatively large for g-C3N4-related samples. This relatively large specific surface area can be attributed to the inhibition of graphene-like sheet stacking due to the simultaneous synthesis with tin oxide. This is consistent with the absence of sharp diffraction peaks related to sheet stacking in the XRD patterns (Figure S3).
Next, we discuss the photodegradation performance of the CNSnO composite. Figure 3 shows the extent of decrease in the PL peak intensity around 305 nm of E2 after 1 h of photoirradiation of the solutions including CNSnO-0 and CNSnO-0.3 composites. (24) As shown in the figure, the photoirradiation of CNSnO-0 causes no significant change in the E2 peak shape, albeit for a light decrease in the peak’s PL intensity, suggesting that E2 degradation has hardly occurred. By contrast, the photoirradiation of CNSnO-0.3 caused the peak intensity around 305 nm to decrease significantly after 1 h of photoirradiation, and a new broad peak appeared on the high-wavelength side. This indicates that upon using CNSnO-0.3, E2 is decomposed by light irradiation, leading to a decrease in the peak intensity around 305 nm and the formation of new broad peaks on the high-wavelength side due to the generation of decomposition products. In other words, the carbon nitride CNSnO-0, which is structurally similar to g-C3N4, does not cause E2 photodegradation on its own. By contrast, E2 degradation becomes possible on carbon nitride with the addition of Sn oxides. Although the amount of Sn oxide has not been optimized, we predict that the performance is sufficient at a level close to that of CNSnO-0.3, because using CNSnO-0.6 that includes twice the amount of Sn did not significantly improve the performance. For these reasons, this paper will focus on the data for CNSnO-0.3 in the main text.

Figure 3

Figure 3. PL intensity of E2 (a) before photoirradiation, and after photoirradiation for 1 h with (b) CNSnO-0 and (c) CNSnO-0.3.

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In this study, we did not analyze the photodegradation process of E2 when using CNSnO-0.3 as the photocatalyst. However, based on previous reports, it is believed that the degradation proceeds via the intermediate 10ε-17β-dihydroxy-1,4-estradien-3-one (DEO) (Figure S2). (25,26) As the degradation progresses, the biological impact of E2 is, of course, eliminated. Additionally, it has been reported that the interaction of DEO, the intermediate product, with estrogen receptors is significantly reduced compared to E2. (25,26)
Next, we discuss the changes in E2 photodegradation by CNSnO-0.3 with the duration of light irradiation. As shown in Figure 4A, it is evident that the PL intensity of E2 decreases with increasing the irradiation time. The plot in the figure represents the integrated intensity of the peak around 305 nm as a function of the irradiation time.

Figure 4

Figure 4. (A) PL intensity of E2 after photoirradiation with CNSnO-0.3 for (a) 0, (b) 0.5, (c) 1.0, and (d) 2.0 h. (B) Integrated PL intensity of E2 as a function of photoirradiation time.

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As observed in Figure 4B, the peak intensity exhibits an exponential decrease with respect to the irradiation time (Figure S9). Considering that the peak intensity is proportional to the concentration of E2, we calculated the first-order rate constant to be k = 3.34 (0.14) × 10–2 (min–1). (27) This rate indicates the effectiveness of E2 decomposition using the photocatalyst developed in this study.
We conducted multiple cycles of E2 photodegradation reactions followed by the recovery of CNSnO composite, and confirmed that there is insignificant difference in performance at least during the first three cycles (see Figure S10). It should be noted that while Figure S10 shows the cycling data for CNSnO-0.6, the durability of CNSnO-0.3 is not expected to differ significantly. This suggests that the efficiency of the E2 photodegradation reaction remains consistent over these cycles, highlighting the potential for cyclic utilization of CNSnO composites in the context of such photodegradation reactions.
Finally, we discuss the mechanism by which CNSnO composites contribute to the photodegradation of E2. To understand the mechanism of E2 photodecomposition by CNSnO-0.3, the surface state of CNSnO-0.3 was examined. The ζ potentials of CNSnO-0 and CNSnO-0.3 in pure water were measured using a Zetasizer Nano ZS (Malvern Panalytical Ltd., UK). The measured ζ potentials were both negative (approximately −35 mV for CNSnO-0 and −55 mV for CNSnO-0.3), indicating that the surface potential of both samples is negative (Table S3). In photocatalytic reactions, it is plausible that the adsorption of the positively polarized parts of water or E2 onto the catalyst surface is the starting point, and this aspect appears to be common to both samples. As previously discussed, the synthesized carbon nitride is structurally similar to g-C3N4. However, the band gap of CNSnO-0 (around 2.55 eV), which was evaluated by performing Kubelka–Munk analysis on the observed UV–vis spectrum (Figure S11), is slightly smaller than that of g-C3N4 (@2.7 eV). (28) This may be related to the fact that the carbon nitride synthesized in this study is slightly nitrogen-rich, as the band gap of g-C3N5 has been reported to decrease to as low as 1.76 eV. (23) Nevertheless, the results confirm that the synthesized carbon nitride is capable of absorbing visible light.
To confirm the bottom energy position of the conduction band in CNSnO-0.3, AC impedance measurements were performed in 1 M KCl aqueous solution, and the complex capacitance was obtained for a Mott–Schottky plot (Figure S12). As shown in Figure S12, the flat-band potential is approximately −1.2 V (vs Ag/AgCl). Since the potential of the Ag/AgCl reference electrode is about +0.2 V relative to the standard hydrogen electrode, it is evident that the conduction band bottom is sufficiently higher than the redox equilibrium potential of oxygen.
Unfortunately, the detailed structure of the Sn oxide contained in the composite is not well understood. However, from XPS, it can be concluded that Sn is in its tetravalent state, suggesting an oxide close to SnO2. (29) While detailed reports exist on the band gap (approximately 3.65 eV) and band positions of bulk SnO2, the Sn oxide synthesized in this study consists of amorphous Sn(IV) oxides or ultra fine SnO2 crystals, which prevents the direct use of the band structure of bulk SnO2. Furthermore, SnO2 quantum dots have been reported to have varying band positions and a smaller band gap depending on the synthesis method. (30) However, even with the reduction due to presence of quantum dots, the band gap is unlikely to be smaller than that of carbon nitride. Furthermore, SnO2 is an n-type semiconductor with its Fermi level near the bottom of the conduction band, while the Fermi level of carbon nitride is near the center of the band gap. (31,32) Therefore, assuming the alignment of the Fermi levels of SnO2 and carbon nitride results in the schematic band diagram shown in Figure 5. Furthermore, as discussed in the XPS section, the presence of lower-valence tin oxides cannot be ruled out. However, even in that case, the mechanism of E2 photooxidative decomposition by the CNSnO photocatalyst as depicted in Figure 5 is still valid. This is because, although lower-valence tin oxides have a smaller band gap compared to SnO2, there is not expected to be a significant change in the band alignment with g-CN. In addition to the above, we confirmed through PL measurements whether the separation of excited electron and hole carriers, as shown in Figure 5, is actually occurring in the CNSnO composites (Figure S13). As shown in Figure S13, the PL intensity of CNSnO-0.3 is significantly reduced compared to CNSnO-0. This suggests that the carrier separation, as indicated in Figure 5, is indeed occurring.

Figure 5

Figure 5. Schematic band diagram of CNSnO composite photocatalyst to explain the photodegradation of E2.

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According to the band diagram in Figure 5, we expect that the oxidative decomposition reaction of E2 is induced by holes in the valence band of carbon nitride. On the other hand, reduction reaction should occur to some extent in the conduction band of Sn oxide. To investigate this, ESR experiments were performed using DMPO as a radical trap agent, as described in the experimental section. DMPO can trap both peroxide ion radicals and OH radicals. However, the ESR spectra of DMPO trapped with peroxide ion radicals and DMPO trapped with OH radicals are distinctly different. When comparing the previous research (for example, Figure 9 in ref (33)) with Figure 6, it is believed that the radical generated in this experiment is a peroxide ion radical. (33) However, it is also possible that OH radicals are generated via peroxide ions. Therefore, OH radicals are also described in Figure 5. For the E2 photooxidative decomposition by the CNSnO photocatalyst, in addition to the direct oxidation of E2 by holes generated through photoexcitation as depicted in Figure 5, oxidation by OH radicals can also be considered. Ohko et al. have reported that E2 decomposes through DEO via both photooxidation and OH radical oxidation. (25) It is possible that in the CNSnO photocatalyst as well, E2 decomposition proceeds via these two oxidation pathways. The important point is that the reduction reaction of oxygen occurs as the counter-reaction to the E2 photooxidative decomposition. In this experiment, oxygen was not intentionally dissolved in the solution, yet E2 was efficiently photodegraded. This suggests that the photocatalyst developed in this study can be used for the photodegradation of estrogen and potentially other endocrine disruptors in river water.

Figure 6

Figure 6. ESR spectra of radical adducts trapped by DMPO (a) before and (b) after photoirradiation.

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Conclusions

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Several types of composites consisting of tin oxide nanoparticles and graphene-like carbon nitride (g-CN) were synthesized by heating a mixture of urea and tin acetate at 550 °C for 2 h under N2 flow in an electric furnace. FT-IR measurements revealed that the obtained g-CN possesses structural units similar to g-C3N4, a well-studied graphite-like carbon nitride. However, unlike g-C3N4, sharp diffraction lines were not observed in the XRD diffraction pattern of g-CN, indicating lower crystallinity. Elemental analysis showed that g-CN is slightly nitrogen-rich compared to g-C3N4, and UV–vis measurements indicated that the band gap (2.55 eV) of g-CN is slightly smaller than that of g-C3N4 (2.70 eV). When simulated solar light was irradiated on CNSnO-0.3, it efficiently decomposed 17β-estradiol (E2), a natural estrogen. The degradation rate constant was evaluated to be k = 3.34 (0.14) × 10–2 (min–1). Peroxide ion radicals were detected in ESR measurements from the irradiated solution, suggesting that peroxide ion radicals are generated through the oxygen photoreduction as the counter-reaction of the oxidative decomposition of E2.

Supporting Information

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The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.4c03390.

  • Figure S1. Crystal structure of g-C3N4, S2. Oxidative degradation process of 17β-estradiol (E2), S3. XRD patterns of (a) CNSnO-0, (b) CNSnO-0.3 and (c) SnO2 crystal, S4. XRD pattern of g-C3N4 prepared from melamine, S5. (A) Sn 3d XPS spectrum of SnO2 powder sample. (B) C 1s and (C) O 1s XPS spectra of CNSnO-0.3, S6. FE-SEM images of (A) CNSnO-0 and (B) CNSnO-0.3, S7. TEM images of CNSnO-0.3, S8. EDS spectrum of CNSnO-0.3. N, O and Sn mapping images of CNSnO-0.3, S9. The figure with the vertical axis of Figure 4B replotted on a logarithmic scale, S10. Cycling performance of CNSnO-0.6, S11. Tauc plot of CNSnO-0, S12. Mott–Schottky plot of CNSnO-0.3, S13. PL spectra of (a) CNSnO-0 and (b) CNSnO-0.3. Table S1. XPS peak position and peak height of CNSnO-0.3 and SnO2 powder sample, S2. BET specific surface area of CNSnO samples, S3. ζ Potential of CNSnO-0 and −0.3 (PDF)

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Author Information

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  • Corresponding Author
  • Authors
    • Yuzuki Amino - Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
    • Ayar Al-zubaidi - Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan;  Orcidhttps://orcid.org/0000-0001-6032-0207
    • Yosuke Ishii - Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan;  Orcidhttps://orcid.org/0000-0003-0334-2228
  • Notes
    The authors declare no competing financial interest.

Acknowledgments

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This work was financially supported by JSPS KAKENHI grant number 23K23448, by JKA and its promotion funds from KEIRIN RACE.

References

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This article references 33 other publications.

  1. 1
    Yilmaz, B.; Terekeci, H.; Sandal, S.; Kelestimur, F. Endocrine disrupting chemicals: exposure, effects on human health, mechanism of action, models for testing and strategies for prevention. Rev. Endocr. Metab. Disord. 2020, 21, 127– 147,  DOI: 10.1007/s11154-019-09521-z
    Google Scholar
    1
    Endocrine disrupting chemicals: exposure, effects on human health, mechanism of action, models for testing and strategies for prevention
    Yilmaz, Bayram; Terekeci, Hakan; Sandal, Suleyman; Kelestimur, Fahrettin
    Reviews in Endocrine & Metabolic Disorders (2020), 21 (1), 127-147CODEN: REMDCG; ISSN:1389-9155. (Springer)
    A review. Endocrine Disrupting Chems. (EDCs) are a global problem for environmental and human health. They are defined as "an exogenous chem., or mixt. of chems., that can interfere with any aspect of hormone action". It is estd. that there are about 1000 chems. with endocrine-acting properties. EDCs comprise pesticides, fungicides, industrial chems., plasticizers, nonylphenols, metals, pharmaceutical agents and phytoestrogens. Human exposure to EDCs mainly occurs by ingestion and to some extent by inhalation and dermal uptake. Most EDCs are lipophilic and bioaccumulate in the adipose tissue, thus they have a very long half-life in the body. It is difficult to assess the full impact of human exposure to EDCs because adverse effects develop latently and manifest at later ages, and in some people do not present. Some EDCs exert obesogenic effects that result in disturbance in energy homeostasis. Interference with hypothalamo-pituitary-thyroid and adrenal axes has also been reported. In this review, potential EDCs, their effects and mechanisms of action, epidemiol. studies to analyze their effects on human health, bio-detection and chem. identification methods, difficulties in extrapolating exptl. findings and studying endocrine disruptors in humans and recommendations for endocrinologists, individuals and policy makers will be discussed in view of the relevant literature.
  2. 2
    Lintelmann, J.; Katayama, A.; Kurihara, N.; Shore, L.; Wenzel, A. Endocrine disruptors in the environment (IUPAC Technical Report). Pure Appl. Chem. 2003, 75, 631– 681,  DOI: 10.1351/pac200375050631
    Google Scholar
    There is no corresponding record for this reference.
  3. 3
    Peng, Y.; Wang, J.; Wu, C. Determination of Endocrine Disruption Potential of Bisphenol A Alternatives in Food Contact Materials Using In Vitro Assays: State of the Art and Future Challenges. J. Agric. Food Chem. 2019, 67, 12613– 12625,  DOI: 10.1021/acs.jafc.9b01543
    Google Scholar
    3
    Determination of Endocrine Disruption Potential of Bisphenol A Alternatives in Food Contact Materials Using In Vitro Assays: State of the Art and Future Challenges
    Peng, Ying; Wang, Jieliang; Wu, Changqing
    Journal of Agricultural and Food Chemistry (2019), 67 (46), 12613-12625CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)
    A review. Alternatives to Bisphenol A (BPA) are developed for food contact materials due to increasing evidence of exposure-correlated harmful effects of BPA. In vitro assays provide the fast, affordable, and mechanism insightful ways to screen endocrine disruption (ED) which is a major concern of new BPA alternatives. In this review, we summarize the safety and regulation information of the alternatives to BPA, review the state of the art of in vitro assays for ED evaluation, highlight their advantages and limitations, and discuss the challenges and future research needs. Our review shows that ligand binding, reporter gene, cell proliferation, and steroidogenesis are four commonly used in vitro assays to det. the ED at the response of receptor, gene transcription, and whole cell level. Major challenges are found from in vitro-in vivo translation and identification of ED chems. in polymers. More studies on these areas are needed in the future.
  4. 4
    Phillips, P. J.; Chalmers, A. T.; Gray, J. L.; Kolpin, D. W.; Foreman, W. T.; Wall, G. R. Combined Sewer Overflows: An Environmental Source of Hormones and Wastewater Micropollutants. Environ. Sci. Technol. 2012, 46, 5336– 5343,  DOI: 10.1021/es3001294
    Google Scholar
    4
    Combined Sewer Overflows: An Environmental Source of Hormones and Wastewater Micropollutants
    Phillips, P. J.; Chalmers, A. T.; Gray, J. L.; Kolpin, D. W.; Foreman, W. T.; Wall, G. R.
    Environmental Science & Technology (2012), 46 (10), 5336-5343CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
    Data collected at a wastewater treatment plant (WWTP) in Burlington, Vermont, serving 30,000 people assessed the relative contribution of combined sewer overflow (CSO) bypass flows and treated wastewater effluent to the steroid hormone and other wastewater micro-pollutant (WMP) load from a WWTP to a lake. Flow-weighted composite samples were collected for 13 mo at this WWTP from CSO bypass flows or treatment plant influent flows (n = 28) and treated effluent discharges (n = 22). Although CSO discharges represent 10% of the total annual water discharge (CSO plus treated plant effluent discharges) from the WWTP, CSO discharges contributed 40-90% of the annual hormones and WMP load with high (>90%) wastewater treatment removal efficiency. Compds. with low removal efficiencies (<90%) had <10% of their annual load contributed by CSO discharges. Estrogens, androgens, and WMP concns. were generally 10 times higher in CSO vs. treated wastewater discharges. Compd. concns. in CSO discharges generally decreased with increasing flow due to wastewater diln. by rainfall runoff. Hormone and many WMP concns. from treated wastewater could increase with increasing flow due to decreasing removal efficiency.
  5. 5
    Gross-Sorokin, M. Y.; Roast, S. D.; Brighty, G. C. Assessment of Feminization of Male Fish in English Rivers by the Environment Agency of England and Wales. Environ. Health Perspect. 2006, 114, 147– 151,  DOI: 10.1289/ehp.8068
    Google Scholar
    There is no corresponding record for this reference.
  6. 6
    Luo, J.; Zhang, S.; Sun, M.; Yang, L.; Luo, S.; Crittenden, J. C. A Critical Review on Energy Conversion and Environmental Remediation of Photocatalysts with Remodeling Crystal Lattice, Surface, and Interface. ACS Nano 2019, 13, 9811– 9840,  DOI: 10.1021/acsnano.9b03649
    Google Scholar
    6
    A critical review on energy conversion and environmental remediation of photocatalysts with remodeling crystal lattice, surface, and interface
    Luo, Jinming; Zhang, Shuqu; Sun, Meng; Yang, Lixia; Luo, Shenglian; Crittenden, John C.
    ACS Nano (2019), 13 (9), 9811-9840CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    A review. Solar energy is a renewable resource that can supply our energy needs in the long term. A semiconductor photocatalysis that is capable of utilizing solar energy has appealed to considerable interests for recent decades, owing to the ability to aim at environmental problems and produce renewal energy. Much effort has been put into the synthesis of a highly efficient semiconductor photocatalyst to promote its real application potential. Hence, we reviewed the most advanced methods and strategies in terms of (i) broadening the light absorption wavelengths, (ii) design of active reaction sites, and (iii) control of the electron-hole (e--h+) recombination, while these three processes could be influenced by remodeling the crystal lattice, surface, and interface. Addnl., we individually examd. their current applications in energy conversion (i.e., hydrogen evolution, CO2 redn., nitrogen fixation, and oriented synthesis) and environmental remediation (i.e., air purifn. and wastewater treatment). Overall, in this review, we particularly focused on advanced photocatalytic activity with simultaneous wastewater decontamination and energy conversion and further enriched the mechanism by proposing the electron flow and substance conversion. Finally, this review offers the prospects of semiconductor photocatalysts in the following three vital (distinct) aspects: (i) the large-scale prepn. of highly efficient photocatalysts, (ii) the development of sustainable photocatalysis systems, and (iii) the optimization of the photocatalytic process for practical application.
  7. 7
    UshaVipinachandran, V.; Rajendran, S.; Haroon, K. H. B.; Ashokan, I.; Mondal, A.; Bhunia, S. K. Detoxification of Endocrine Disruptors in Water Using Visible-LightActive Nanostructures: A Review. ACS Appl. Nano Mater. 2020, 3, 11659– 11687,  DOI: 10.1021/acsanm.0c02974
    Google Scholar
    There is no corresponding record for this reference.
  8. 8
    Zhu, Q.; Xu, Z.; Qiu, B.; Xing, M.; Zhang, J. Emerging Cocatalysts on g-C3N4 for Photocatalytic Hydrogen Evolution. Small 2021, 17, 2101070  DOI: 10.1002/smll.202101070
    Google Scholar
    8
    Emerging Cocatalysts on g-C3N4 for Photocatalytic Hydrogen Evolution
    Zhu, Qiaohong; Xu, Zehong; Qiu, Bocheng; Xing, Mingyang; Zhang, Jinlong
    Small (2021), 17 (40), 2101070CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)
    A review. Over the past few decades, graphitic carbon nitride (g-C3N4) has arisen much attention as a promising candidate for photocatalytic hydrogen evolution reaction (HER) owing to its low cost and visible light response ability. However, the unsatisfied HER performance originated from the strong charge recombination of g-C3N4 severely inhibits the further large-scale application of g-C3N4. In this case, the utilization of cocatalysts is a novel frontline in the g-C3N4-based photocatalytic systems due to the pos. effects of cocatalysts on suppressing charge carrier recombination, reducing the HER overpotential, and improving photocatalytic activity. This summarizes some recent advances about the high-performance cocatalysts based on g-C3N4 toward HER. Specifically, the functions, design principle, classification, modification strategies of cocatalysts, as well as their intrinsic mechanism for the enhanced photocatalytic HER activity are discussed here. Finally, the pivotal challenges and future developments of cocatalysts in the field of HER are further proposed.
  9. 9
    Yu, X.; Ng, S.; Putri, L. K.; Tan, L.; Mohamed, A. R.; Ong, W. Point-Defect Engineering: Leveraging Imperfections in Graphitic Carbon Nitride (g-C3N4) Photocatalysts toward Artificial Photosynthesis. Small 2021, 17, 2006851  DOI: 10.1002/smll.202006851
    Google Scholar
    9
    Point-defect engineering: Leveraging imperfections in graphitic carbon nitride (g-C3N4) photocatalysts toward artificial photosynthesis
    Yu, Xinnan; Ng, Sue-Faye; Putri, Lutfi Kurnianditia; Tan, Lling-Lling; Mohamed, Abdul Rahman; Ong, Wee-Jun
    Small (2021), 17 (48), 2006851CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)
    A review. Graphitic carbon nitride (g-C3N4) is a kind of ideal metal-free photocatalysts for artificial photosynthesis. At present, pristine g-C3N4 suffers from small sp. surface area, poor light absorption at longer wavelengths, low charge migration rate, and a high recombination rate of photogenerated electron-hole pairs, which significantly limit its performance. Among a myriad of modification strategies, point-defect engineering, namely tunable vacancies and dopant introduction, is capable of harnessing the superb structural, textural, optical, and electronic properties of g-C3N4 to acquire an ameliorated photocatalytic activity. In view of the burgeoning development in this pacey field, a timely review on the state-of-the-art advancement of point-defect engineering of g-C3N4 is of vital significance to advance the solar energy conversion. Particularly, insights into the intriguing roles of point defects, the synthesis, characterizations, and the systematic control of point defects, as well as the versatile application of defective g-C3N4-based nanomaterials toward photocatalytic water splitting, carbon dioxide redn. and nitrogen fixation will be presented in detail. Lastly, this review will conclude with a balanced perspective on the tech. and scientific hindrances and future prospects. Overall, it is envisioned that this review will open a new frontier to uncover novel functionalities of defective g-C3N4-based nanostructures in energy catalysis.
  10. 10
    Xiao, J.; Xie, Y.; Rabeah, J.; Bruckner, A.; Cao, H. Visible-Light Photocatalytic Ozonation Using Graphitic C3N4 Catalysts: A Hydroxyl Radical Manufacturer for Wastewater Treatment. Acc. Chem. Res. 2020, 53, 1024– 1033,  DOI: 10.1021/acs.accounts.9b00624
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    Visible-Light Photocatalytic Ozonation Using Graphitic C3N4 Catalysts: A Hydroxyl Radical Manufacturer for Wastewater Treatment
    Xiao, Jiadong; Xie, Yongbing; Rabeah, Jabor; Bruckner, Angelika; Cao, Hongbin
    Accounts of Chemical Research (2020), 53 (5), 1024-1033CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
    Over the past 20 yr, photocatalytic ozonation (light/O3/photocatalyst), an independent advanced oxidn. process (AOP) proposed in 1996, demonstrated its robust oxidn. capacity and potential for practical wastewater treatment using sunlight and air (O3 source). However, its development is restricted by two major issues: a lack of break-through catalysts working under visible light (42-43% of sunlight energy) and ambiguous property-activity relationships; and unclear fundamental reasons underlying its high yield of OH-. This paper summarizes the substantial contributions to solve these issues, including: new-generation graphitic carbon nitride (g-C3N4) catalysts with excellent performance for photocatalytic ozonation under visible light; charge carrier transfer and reactive oxygen species (ROS) evolution mechanisms; property-activity relationships; and chem. and working stabilities of g-C3N4 catalysts. Based on these results, principles/directions for future catalyst design/optimization are discussed, and a new concept of integrating solar photocatalytic ozonation with catalytic ozonation in one facility for continuous wastewater treatment regardless of sunlight availability, is proposed. This begins from the finding that bulk/nanosheet/nanoporous g-C3N4 triggers a strong synergy between visible light (vis) and O3, causing efficient mineralization of a variety of org. pollutants. Using bulk g-C3N4 as an example, photocatalytic ozonation (vis/O3/g-C3N4) mineralized oxalic acid (model pollutant) at a rate 95.8 times higher than the sum of photocatalytic oxidn. (vis/O2/g-C3N4) and ozonation. To unravel this synergism, the authors developed a method based on in-situ ESR spectroscopy in conjunction with an online spin trapping method to monitor, under realistic aq. conditions, generation and transfer of photo-induced charge carriers and their reaction with dissolved O3/O2 to form ROS. The presence of only 2.1 mol percent O3 in the inlet O2 gas stream can trap 1-2 times more conduction band electrons than pure O2 and shifts the reaction pathway from inefficient three-electron redn. of O2 (O2 → O2- → HO2- → H2O2 → OH-) to more efficient one-electron redn. of O3 (O3 → O3- → HO3- → OH-), thereby increasing the yield of OH- by a factor of 17. Next, the band structure as a decisive factor for catalytic performance was confirmed and a new concept to resolve this relationship, involving the no. of reactive charge carriers, was established. An optimum balance between the no. and reducing ability of photo-induced electrons, which depends on the interplay between band gap and conduction band edge potential, is a key property for highly active g-C3N4 catalysts. It was demonstrated g-C3N4 is chem. stable toward O3 and O2-, but OH- can tear and oxidize its heptazine units to form cyameluric acid and further release NO3- to the aq. environment. Fortunately, OH- usually attacks wastewater org. pollutants in preference to g-C3N4, thereby preserving the g-C3N4 working stability and the steady operation of photocatalytic ozonation. This AOP, which serves as an in-situ OH- generator is of interest to a broad chem. world since OH- are active species for environmental applications and for org. synthesis, polymn., zeolite synthesis, and protein foot-printing.
  11. 11
    Guan, R.; Li, J.; Zhang, J.; Zhao, Z.; Wang, D.; Zhai, H.; Sun, D. Photocatalytic Performance and Mechanistic Research of ZnO/g-C3N4 on Degradation of Methyl Orange. ACS Omega 2019, 4, 20742– 20747,  DOI: 10.1021/acsomega.9b03129
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    11
    Photocatalytic Performance and Mechanistic Research of ZnO/g-C3N4 on Degradation of Methyl Orange
    Guan, Renquan; Li, Jiaxin; Zhang, Junkai; Zhao, Zhao; Wang, Dandan; Zhai, Hongju; Sun, Dewu
    ACS Omega (2019), 4 (24), 20742-20747CODEN: ACSODF; ISSN:2470-1343. (American Chemical Society)
    Highly dispersed ZnO/g-C3N4 composites with different doping ratios of g-C3N4 were prepd. by a hydrothermal method. The prepn. method is simple and the energy consumption is low. The composite samples were used to degradate the Methyl orange soln. They all showed excellent photocatalytic activity and cycling stability. The optimal loading content of g-C3N4 was studied, and the mechanism of enhanced photocatalytic activity was studied. This study provides a promising photocatalytic material for the removal of org. pollutants.
  12. 12
    Gu, Y.; Li, S.; Li, M.; Wang, X.; Liu, Y.; Shi, K.; Bai, X.; Yao, Q.; Wu, Z.; Yao, H. Recent advances in g-C3N4-based photo-enzyme catalysts for degrading organic pollutants. RSC Adv. 2023, 13, 937– 947,  DOI: 10.1039/D2RA06994F
    Google Scholar
    There is no corresponding record for this reference.
  13. 13
    Liu, R.; Chen, Z.; Yao, Y.; Li, Y.; Cheema, W. A.; Wang, D.; Zhu, S. Recent advancements in g-C3N4-based photocatalysts for photocatalytic CO2 reduction: a mini review. RSC Adv. 2020, 10, 29408– 29418,  DOI: 10.1039/D0RA05779G
    Google Scholar
    13
    Recent advancements in g-C3N4-based photocatalysts for photocatalytic CO2 reduction: a mini review
    Liu Runlu; Yao Yao; Li Yao; Zhu Shenmin; Chen Zhixin; Cheema Waqas A; Wang Dawei
    RSC advances (2020), 10 (49), 29408-29418 ISSN:.
    Carbon dioxide (CO2) is a very important micro-molecular resource. Using CO2 captured from the atmosphere for high-output synthesis of chemicals as raw materials has great significance and potential for various industrial applications. Since the industrial revolution in the 18(th) century, manmade CO2 emission has increased by 45%, which negatively impacts the planetary climate by the so-called greenhouse effect. Therefore, high-efficiency photocatalysis and photocatalysts for CO2 conversion have become the most important challenges and milestones throughout the world. In consideration of this, various catalysts have been explored. Among these, graphitic carbon nitride (g-C3N4) as a semiconductor is emerging as a highly promising photocatalyst for removing CO2 from the atmosphere. Moreover, due to its excellent chemical stability and unique band structure, g-C3N4 has exhibited significant application potential for photocatalysis. This review summarizes the advancements that have been made in the synthesis and photocatalytic applications of g-C3N4-based catalysts for CO2 reduction in recent years and explains the future challenges and prospects in this vital area of research.
  14. 14
    Liebig, J. Uber einige stickstoff - verbindungen. Ann. Pharm. 1834, 10, 1– 47,  DOI: 10.1002/jlac.18340100102
    Google Scholar
    There is no corresponding record for this reference.
  15. 15
    Wang, X.; Maeda, K.; Thomas, A.; Takanabe, K.; Xin, G.; Carlsson, J. M.; Domen, K.; Antonietti, M. A metal-free polymeric photocatalyst for hydrogen production from water under visible light. Nat. Mater. 2009, 8, 76– 80,  DOI: 10.1038/nmat2317
    Google Scholar
    15
    A metal-free polymeric photocatalyst for hydrogen production from water under visible light
    Wang, Xinchen; Maeda, Kazuhiko; Thomas, Arne; Takanabe, Kazuhiro; Xin, Gang; Carlsson, Johan M.; Domen, Kazunari; Antonietti, Markus
    Nature Materials (2009), 8 (1), 76-80CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)
    The prodn. of hydrogen from water using a catalyst and solar energy is an ideal future energy source, independent of fossil reserves. For an economical use of water and solar energy, catalysts that are sufficiently efficient, stable, inexpensive and capable of harvesting light are required. Here, we show that an abundant material, polymeric carbon nitride, can produce hydrogen from water under visible-light irradn. in the presence of a sacrificial donor. Contrary to other conducting polymer semiconductors, carbon nitride is chem. and thermally stable and does not rely on complicated device manufg. The results represent an important first step towards photosynthesis in general where artificial conjugated polymer semiconductors can be used as energy transducers.
  16. 16
    Hassani, A.; Faraji, M.; Eghbali, P. Facile fabrication of mpg-C3N4/Ag/ZnO nanowires/Zn photocatalyst plates for photodegradation of dye pollutant. J. Photochem. Photobiol., A 2020, 400, 112665  DOI: 10.1016/j.jphotochem.2020.112665
    Google Scholar
    16
    Facile fabrication of mpg-C3N4/Ag/ZnO nanowires/Zn photocatalyst plates for photodegradation of dye pollutant
    Hassani, Aydin; Faraji, Masoud; Eghbali, Paria
    Journal of Photochemistry and Photobiology, A: Chemistry (2020), 400 (), 112665CODEN: JPPCEJ; ISSN:1010-6030. (Elsevier B.V.)
    Mpg-C3N4/Ag/ZnO NWs/Zn photocatalyst plates were fabricated through facile dip-coating process of silver and mesoporous graphitic carbon nitride onto zinc oxide nanowires previously formed by electrochem. anodizing of Zn plates. The structure, optical and electrochem. characterizations of the fabricated samples were investigated by XRD, FESEM, EDX, TEM, FTIR, BET, PL, UV-vis DRS, and EIS analyses. To evaluate the photocatalytic activity of the plates, the main key factors such as no. of photocatalyst plates, dye concn., initial pH, and reaction time for the degrdn. of Direct Orange 26 dye under UV light illumination were studied. The best photocatalytic efficiency of 94% was achieved using four photocatalyst plates, 10 mg/L DO26, and pH = 6 in 120 min of reaction time. The integration of the mpg-C3N4/Ag/ZnO NWs/Zn plates, adsorption, and photolysis inferred the existence of a synergy index of 5 for the degrdn. of target pollutant. In the presence of edetate disodium and ethanol, degrdn. efficiency of DO26 was remarkably dropped to 43.6% and 19.3% by the photocatalytic process resp., indicating the major role of h+ and -OH in the destruction of target mols. Fabrication of the mpg-C3N4/Ag/ZnO NWs/Zn plates is anticipated to be a rational design for photocatalytic degrdn. of various pollutants.
  17. 17
    Hassani, A.; Eghbali, P.; Metin, O. Sonocatalytic removal of methylene blue from water solution by cobalt ferrite/mesoporous graphitic carbon nitride (CoFe2O4/mpg-C3N4) nanocomposites: response surface methodology approach. Environ. Sci. Pollut. Res. Int. 2018, 25, 32140– 32155,  DOI: 10.1007/s11356-018-3151-3
    Google Scholar
    17
    Sonocatalytic removal of methylene blue from water solution by cobalt ferrite/mesoporous graphitic carbon nitride (CoFe2O4/mpg-C3N4) nanocomposites: response surface methodology approach
    Hassani Aydin; Eghbali Paria; Metin Onder
    Environmental science and pollution research international (2018), 25 (32), 32140-32155 ISSN:.
    In this study, cobalt ferrite/mesoporous graphitic carbon nitride (CoFe2O4/mpg-C3N4) nanocomposites were successfully synthesized by using a two-step protocol. Firstly, monodispersed CoFe2O4 nanoparticles (NPs) were synthesized via thermal decomposition of metal precursors in a hot surfactant solution and then they were assembled on mpg-C3N4 via a liquid phase self-assembly method. The sonocatalytic performance of as-synthesized CoFe2O4/mpg-C3N4 nanocomposites was evaluated on the methylene blue (MB) removal from water under ultrasonic irradiation. For this purpose, response surface methodology (RSM) based on central composite design (CCD) model was successfully utilized to optimize the MB removal over CoFe2O4/mpg-C3N4 nanocomposites. Analysis of variance (ANOVA) was applied to investigate the significance of the model. The results predicted by the model were obtained to be in reasonable agreement with the experimental data (R(2) = 0.969, adjusted R(2) = 0.942). Pareto analysis demonstrated that pH of the solution was the most effective parameter on the sonocatalytic removal of MB by CoFe2O4/mpg-C3N4 nanocomposites. The optimum catalyst dose, initial dye concentration, pH, and sonication time were set as 0.25 g L(-1), 8 mg L(-1), 8, and 45 min, respectively. The high removal efficiency of MB dye (92.81%) was obtained under optimal conditions. The trapping experiments were done by using edetate disodium, tert-butyl alcohol, and benzoquinone. Among the reactive radicals, (•)OH played a more important role than h(+) and [Formula: see text] in the MB dye removal process. Moreover, a proposed mechanism was also presented for the removal of MB in the presence of CoFe2O4/mpg-C3N4 nanocomposites under the optimized sonocatalytic conditions. Finally, a reusability test of the nanocomposites revealed a just 9.6% decrease in their removal efficiency after five consecutive runs.
  18. 18
    Hassani, A.; Krishnan, S.; Scaria, J.; Eghbali, P.; Nidheesh, P. V. Z-scheme photocatalysts for visible-light-driven pollutants degradation: A review on recent advancements. Curr. Opin. Solid State Mater. Sci. 2021, 25, 100941  DOI: 10.1016/j.cossms.2021.100941
    Google Scholar
    18
    Z-scheme photocatalysts for visible-light-driven pollutants degradation: A review on recent advancements
    Hassani, Aydin; Krishnan, Sukanya; Scaria, Jaimy; Eghbali, Paria; Nidheesh, P. V.
    Current Opinion in Solid State & Materials Science (2021), 25 (5), 100941CODEN: COSSFX; ISSN:1359-0286. (Elsevier Ltd.)
    A review. Harvesting solar energy for energy and environmental applications is an ever-fascinating field of research. Although semiconductor photocatalysis is the potential tool for recalcitrant degrdn., it still suffers from rapid recombination, inability to utilize visible light, and lower photocatalytic performance. Recently, the Z-scheme photocatalysts are becoming research hotspots for their strong redox ability, charge carrier sepn., and ability to exploit visible light. This review provides insights into the fundamental mechanism, synthesis strategies, and characterization techniques of Z-scheme photocatalysts. The recent advancements in their applications in visible-light-driven pollutants degrdn. are also reviewed.
  19. 19
    Ji, H.; Fan, Y.; Yan, J.; Xu, Y.; She, X.; Gu, J.; Fei, T.; Xu, H.; Li, H. Construction of SnO2/graphene-like g-C3N4 with enhanced visible light photocatalytic activity. RSC Adv. 2017, 7, 36101– 36111,  DOI: 10.1039/C7RA05830F
    Google Scholar
    19
    Construction of SnO2/graphene-like g-C3N4 with enhanced visible light photocatalytic activity
    Ji, Haiyan; Fan, Yamin; Yan, Jia; Xu, Yuanguo; She, Xiaojie; Gu, Jiemin; Fei, Ting; Xu, Hui; Li, Huaming
    RSC Advances (2017), 7 (57), 36101-36111CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)
    In this work, SnO2/graphene-like g-C3N4 (SnO2/GL-C3N4) composite photocatalysts with large surface areas and abundant coupling heterointerfaces were synthesized using a hydrothermal method. The as-prepd. photocatalysts exhibited distinctly manifested efficient visible light activities toward org. pollutant degrdn., demonstrating remarkable synergistic effects between SnO2 and graphene-like g-C3N4 (GL-C3N4). The 25 wt% SnO2/GL-C3N4 composite showed optimal photocatalytic activity under visible light irradn., which was almost 9 and 2.5 times as high as that of SnO2 and GL-C3N4, resp. In addn., the possible photocatalytic mechanism of rhodamine B (RhB) degrdn. by SnO2/GL-C3N4 under visible light was also discussed in detail. Moreover, this work would provide a facile way for the fabrication of novel two dimension/two dimension (2D/2D) GL-C3N4-based photocatalysts with high and stable performance for pollutant degrdn.
  20. 20
    Putri, L. K.; Ng, B.; Ong, W.; Lee, H. W.; Chang, W. S.; Chai, S. Engineering nanoscale p–n junction via the synergetic dual-doping of p-type boron-doped graphene hybridized with n-type oxygen-doped carbon nitride for enhanced photocatalytic hydrogen evolution. J. Mater. Chem. A 2018, 6, 3181– 3194,  DOI: 10.1039/C7TA09723A
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    Engineering nanoscale p-n junction via the synergetic dual-doping of p-type boron-doped graphene hybridized with n-type oxygen-doped carbon nitride for enhanced photocatalytic hydrogen evolution
    Putri, Lutfi Kurnianditia; Ng, Boon-Junn; Ong, Wee-Jun; Lee, Hing Wah; Chang, Wei Sea; Chai, Siang-Piao
    Journal of Materials Chemistry A: Materials for Energy and Sustainability (2018), 6 (7), 3181-3194CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)
    In this study, an effective 2D-2D heterojunction composite was formulated by hybridizing oxygen doped graphitic carbon nitride (O-gC3N4) with boron doped reduced graphene oxide (B-rGO) using a combined sonication-assisted electrostatic self-assembly approach. Pristine gC3N4 possesses a neg. surface charge, which later transforms into a pos. charge upon doping with elemental oxygen. This reversal of surface charge, which occurred on top of doping, established the opportune electrostatic coupling of pos. charged O-gC3N4 and neg. charged B-rGO. Moreover, the concerted dual doping of both O-gC3N4 and B-rGO, which exhibited n-type and p-type cond., resp., allowed the construction of a nanoscale p-n heterojunction system at the interface, warranting a more effective and rapid charge sepn. and in turn bolstering the photocatalytic hydrogen performance. In particular, the optimal loading content of B-rGO was 2% with a corresponding H2 prodn. rate of 1639 μmol g-1 after 6 h, which is a remarkable 4-fold photocatalytic improvement as compared to that of O-gC3N4. In brief, this study highlights that the dual doping of both gC3N4 and rGO and their hybridization present a powerful strategy to increase the photoactivity of the composite since doping could remarkably modulate their interaction at the heterointerface.
  21. 21
    Fina, F.; Callear, S. K.; Carins, G. M.; Irvine, J. T. S. Structural Investigation of Graphitic Carbon Nitride via XRD and Neutron Diffraction. Chem. Mater. 2015, 27, 2612– 2618,  DOI: 10.1021/acs.chemmater.5b00411
    Google Scholar
    21
    Structural Investigation of Graphitic Carbon Nitride via XRD and Neutron Diffraction
    Fina, Federica; Callear, Samantha K.; Carins, George M.; Irvine, John T. S.
    Chemistry of Materials (2015), 27 (7), 2612-2618CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
    Graphitic carbon nitride (g-C3N4) has, since 2009, attracted great attention for its activity as a visible-light-active photocatalyst for hydrogen evolution. Since it was synthesized in 1834, g-C3N4 has been extensively studied both catalytically and structurally. Although its 2D structure seems to have been solved, its 3D crystal structure has not yet been confirmed. This study attempts to solve the 3D structure of graphitic carbon nitride by means of X-ray diffraction and of neutron scattering. Initially, various structural models are considered and their XRD patterns compared to the measured one. After selecting possible candidates as g-C3N4 structure, neutron scattering is employed to identify the best model that describes the 3D structure of graphitic carbon nitride. Parallel chains of tri-s-triazine units organized in layers with an A-B stacking motif are found to describe the structure of the synthesized graphitic carbon nitride well. A misalignment of the layers is favorable because of the decreased π-π repulsive interlayer interactions.
  22. 22
    Akgul, F. A.; Gumus, C.; Er, A. O.; Farha, A. H.; Akgul, G.; Ufuktepe, Y.; Liu, Z. Structural and electronic properties of SnO2. J. Alloys Compd. 2013, 579, 50– 56,  DOI: 10.1016/j.jallcom.2013.05.057
    Google Scholar
    22
    Structural and electronic properties of SnO2
    Akgul, Funda Aksoy; Gumus, Cebrail; Er, Ali O.; Farha, Ashraf H.; Akgul, Guvenc; Ufuktepe, Yuksel; Liu, Zhi
    Journal of Alloys and Compounds (2013), 579 (), 50-56CODEN: JALCEU; ISSN:0925-8388. (Elsevier B.V.)
    Highly transparent polycryst. thin film of SnO2 (tin dioxide) was deposited using a simple and low cost spray pyrolysis method. The film was prepd. from an aq. soln. of tin tetrachloride (stannic chloride) onto glass substrates at 400°. A range of diagnostic techniques including x-ray diffraction (XRD), UV-visible absorption, at. force microscopy (AFM), SEM, and synchrotron-based XPS were used to investigate structural, optical, and electronic properties of the resulting film. Deposited film was found to be polycryst. A mixt. of SnO and SnO2 phases was obsd. The av. crystallite size of ∼21.3 nm for SnO2 was calcd. by Rietveld method using XRD data. The oxidn. states of the SnO2 thin film were confirmed by the shape anal. of corresponding XPS O 1s, Sn 3d, and Sn 4d peaks using the decompn. procedure. The anal. of the XPS core level peaks showed that the chem. component is non-stoichiometric and the ratio of oxygen to tin (O/Sn) is 1.85 which is slightly under stoichiometry.
  23. 23
    Kumar, P.; Vahidzadeh, E.; Thakur, U. K.; Kar, P.; Alam, K. M.; Goswami, A.; Mahdi, N.; Cui, K.; Bernard, G. M.; Michaelis, V. K.; Shankar, K. C3N5: A Low Bandgap Semiconductor Containing an Azo-Linked Carbon Nitride Framework for Photocatalytic, Photovoltaic and Adsorbent Applications. J. Am. Chem. Soc. 2019, 141, 5415– 5436,  DOI: 10.1021/jacs.9b00144
    Google Scholar
    23
    C3N5: A Low Bandgap Semiconductor Containing an Azo-Linked Carbon Nitride Framework for Photocatalytic, Photovoltaic and Adsorbent Applications
    Kumar, Pawan; Vahidzadeh, Ehsan; Thakur, Ujwal K.; Kar, Piyush; Alam, Kazi M.; Goswami, Ankur; Mahdi, Najia; Cui, Kai; Bernard, Guy M.; Michaelis, Vladimir K.; Shankar, Karthik
    Journal of the American Chemical Society (2019), 141 (13), 5415-5436CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Modification of carbon nitride based polymeric 2D materials for tailoring their optical, electronic and chem. properties for various applications has gained significant interest. The present report demonstrates the synthesis of a novel modified carbon nitride framework with a remarkable 3:5 C:N stoichiometry (C3N5) and an electronic bandgap of 1.76 eV, by thermal deammoniation of melem hydrazine precursor. Characterization revealed that in C3N5 polymer, two s-heptazine units are bridged together with azo linkage, which constitutes an entirely new and different bonding fashion from g-C3N4 where three heptazine units are linked together with tertiary nitrogen. Extended conjugation due to overlap of azo nitrogens and increased electron d. on heptazine nucleus due to the arom. π network of heptazine units lead to an upward shift of the valence band max. resulting in bandgap redn. down to 1.76 eV. XRD, He-ion imaging, HR-TEM, EELS, PL, fluorescence life time imaging, Raman, FTIR, TGA, KPFM etc. clearly show that the properties of C3N5 are distinct from pristine carbon nitride (g-C3N4). When used as an electron transport layer (ETL) in MAPbBr3 based halide perovskite solar cells, C3N5 outperformed g-C3N4, in particular generating an open circuit photovoltage as high as 1.3 V, while C3N5 blended with MAxFA1-xPb(I0.85Br0.15)3 perovskite active layer achieved a photoconversion efficiency (PCE) ≤ 16.7 %. C3N5 was also shown to be an effective visible light sensitizer for TiO2 photoanodes in photoelectrochem. water splitting. Due to its electron-rich character, the C3N5 material displayed instantaneous adsorption of methylene blue from aq. soln. reaching complete equil. within 10 min, which is significantly faster than pristine g-C3N4 and other carbon- based materials. C3N5 coupled with plasmonic silver nanocubes promotes plasmon-exciton co-induced surface catalytic reactions reaching completion at much low laser intensity (1.0 mW) than g-C3N4 which showed sluggish performance even at high laser power (10.0 mW). The relatively narrow bandgap and 2D structure of C3N5 make it an interesting air-stable and temp.-resistant semiconductor for optoelectronic applications while its electron- rich character and intra-sheet cavity make it an attractive supramol. adsorbent for environmental applications.
  24. 24
    Wang, H.; Duan, A.; Mao, J.; Che, B.; Wang, W.; Ma, M.; Wang, Xuedong. Effects of Ionic Liquids on Fluorescence Characteristics of 17α- and 17β-estradiol. J. Fluoresc. 2013, 23, 103– 113,  DOI: 10.1007/s10895-012-1123-4
    Google Scholar
    There is no corresponding record for this reference.
  25. 25
    Ohko, Y.; Iuchi, K.; Niwa, C.; Tatsuma, T.; Nakashima, T.; Iguchi, T.; Kubota, Y.; Fujishima, A. 17β-Estradiol Degradation by TiO2 Photocatalysis as a Means of Reducing Estrogenic Activity. Environ. Sci. Technol. 2002, 36, 4175– 4181,  DOI: 10.1021/es011500a
    Google Scholar
    25
    17β-Estradiol Degradation by TiO2 Photocatalysis as a Means of Reducing Estrogenic Activity
    Ohko, Yoshihisa; Iuchi, Ken-ichiro; Niwa, Chisa; Tatsuma, Tetsu; Nakashima, Tetsuto; Iguchi, Taisen; Kubota, Yoshinobu; Fujishima, Akira
    Environmental Science and Technology (2002), 36 (19), 4175-4181CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
    The degrdn. of 17β-estradiol (E2) in water by TiO2 photocatalysis was investigated; concurrently, the estrogenic activity of the treated water was evaluated during the photocatalytic reactions by an estrogen screening assay. As a result, 10-6M E2 was totally mineralized to CO2 in 1.0 g TiO2/L suspension under UV irradn. for 3 h. 10ε-17β-Dihydroxy-1,4-estradien-3-one and testosterone-like species were elucidated as intermediate products by gas chromatog./mass spectrometry (GC/MS) anal. The mechanisms of E2 degrdn. by TiO2 photocatalysis were discussed not only exptl. but also theor. by calcg. the frontier electron densities of the E2 mol. On the basis of the results obtained, it was concluded that the phenol moiety of the E2 mol., one of the essential functional groups to interact with the estrogen receptor, should be the starting point of the photocatalytic oxidn. of E2. This means that the estrogenic activity should be almost lost concurrently with the initiation of the photocatalytic degrdn. Actually, the estrogenic activities of the intermediate products were negligible. TiO2 photocatalysis could be applied to water treatment to effectively remove natural and synthetic estrogens without producing biol. active intermediary products.
  26. 26
    Zhao, Y.; Hu, H.; Jin, W. Transformation of Oxidation Products and Reduction of Estrogenic Activity of 17β-Estradiol by a Heterogeneous Photo-Fenton Reaction. Environ. Sci. Technol. 2008, 42, 5277– 5284,  DOI: 10.1021/es703253q
    Google Scholar
    26
    Transformation of Oxidation Products and Reduction of Estrogenic Activity of 17β-Estradiol by a Heterogeneous Photo-Fenton Reaction
    Zhao, Yaping; Hu, Jiangyong; Jin, Wei
    Environmental Science & Technology (2008), 42 (14), 5277-5284CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
    A novel photo-Fenton catalyst, α-FeOOH loaded resin (α-FeOOHR), was synthesized and evaluated through transformation of a steroidal endocrine disrupting compds. (EDC), 17β-estradiol (E2), under weak UV irradn. in the presence of H2O2. E2 photodegrdn. intermediates elucidated in detail by GC/MS and LC/MS/MS analyses and detailed reaction pathways are proposed. A yeast-based estrogen screen for E2 and its photodegrdn. intermediates was performed to measure the redn. of estrogenic activity in different water matrixes during the heterogeneous photo-Fenton process. The results showed that α-FeOOHR not only degraded E2 but also removed the estrogenic activity originating from E2, its degrdn. intermediates, and its products. However, the water matrix present in drinking water may impact estrogenic activity redn. The results are important to evaluate the ability of photo-Fenton advanced oxidn. processes in reducing EDCs and their assocd. estrogenicity from drinking water.
  27. 27
    Mitamura, K.; Narukawa, H.; Mizuguchi, T.; Shimada, K. Degradation of estrogen conjugates using titanium dioxide as a photocatalyst. Anal. Sci. 2004, 20, 3– 4,  DOI: 10.2116/analsci.20.3
    Google Scholar
    There is no corresponding record for this reference.
  28. 28
    Zhu, D.; Zhou, Q. Nitrogen doped g-C3N4 with the extremely narrow band gap for excellent photocatalytic activities under visible light. Appl. Catal., B 2021, 281, 119474  DOI: 10.1016/j.apcatb.2020.119474
    Google Scholar
    28
    Nitrogen doped g-C3N4 with the extremely narrow band gap for excellent photocatalytic activities under visible light
    Zhu, Dandan; Zhou, Qixing
    Applied Catalysis, B: Environmental (2021), 281 (), 119474CODEN: ACBEE3; ISSN:0926-3373. (Elsevier B.V.)
    In this work, nitrogen doped g-C3N4 (NCN) with the extremely narrow band gap was prepd. and applied for the photodegrdn. of phenols. Expts. and DFT (the d. functional theory) computation identified that N-doping introduced in the g-C3N4 matrix by substituting C atoms. DFT, PL (photoluminescence) spectra, optical property characteristic and PEC (photoelectrochem.) indicated that NCN possess extremely narrow band gap, efficient photogenerated carrier sepn. and the charge transfer, which enhanced the absorption of visible light and further promoted the photocatalytic activity. As a result, NCN(2:2) showed about twice higher photodegrdn. efficiencies and 3 times rate const. than pristine g-C3N4. The radical trapping expts. showed that •O2- radical and h+ served as crucial active species during the whole photodegrdn. reaction. This work can provide a strategy to enhance the photocatalytic activity of photocatalysts via introduce foreign atoms in matrix.
  29. 29
    Reddy, C. V.; Babu, B.; Vattikuti, S. V. P.; Ravikumar, R. V. S. S. N.; Shim, J. Structural and optical properties of vanadium doped SnO2 nanoparticles with high photocatalytic activities. J. Lumin. 2016, 179, 26– 34,  DOI: 10.1016/j.jlumin.2016.06.036
    Google Scholar
    29
    Structural and optical properties of vanadium doped SnO2 nanoparticles with high photocatalytic activities
    Reddy, Ch. Venkata; Babu, B.; Vattikuti, S. V. Prabhakar; Ravikumar, R. V. S. S. N.; Shim, Jaesool
    Journal of Luminescence (2016), 179 (), 26-34CODEN: JLUMA8; ISSN:0022-2313. (Elsevier B.V.)
    Vanadium (0.01, 0.03 and 0.05 mol%) doped SnO2 nanoparticles have been synthesized using combustion synthesis method. The as-prepd. nanoparticles were characterized using various measurements such as XRD, SEM with EDS, HRTEM, Raman spectroscopy, optical, PL, XPS and FT-IR techniques. The crystal structure and av. particle sizes of the prepd. nanoparticles were confirmed from the XRD. The av. cryst. particle sizes were decreased by increasing the vanadium dopant concn. The presence of vanadium as V4+ species in the host lattice was confirmed by XPS. The band gap energies were decreased by increasing dopant concn. The 0.05 mol% doped sample showed higher photocatalytic activity than undoped, V-1 and V-3 in decompg. rhodamine B (RhB) under UV light irradn. The Raman and IR spectra confirm the fundamental vibration of SnO2 host mols.
  30. 30
    Babu, B.; Reddy, I. N.; Yoo, K.; Kim, D.; Shim, J. Bandgap tuning and XPS study of SnO2 quantum dots. Mater. Lett. 2018, 221, 211– 215,  DOI: 10.1016/j.matlet.2018.03.107
    Google Scholar
    30
    Bandgap tuning and XPS study of SnO2 quantum dots
    Babu, Bathula; Neelakanta Reddy, I.; Yoo, Kisoo; Kim, Dongseob; Shim, Jaesool
    Materials Letters (2018), 221 (), 211-215CODEN: MLETDJ; ISSN:0167-577X. (Elsevier B.V.)
    The authors investigated the influence of annealing temp. on ultra-small SnO2 quantum dots (SQDs) prepd. by a simple chem. redn. process. The structural and optical properties of annealed SQDs were systematically studied by different techniques. The results show that the crystallinity and av. crystallite size of annealed SQDs increased gradually with annealing temp. The av. crystallite size was maintained below 10 nm even for high annealing temps. XPS peak fitting anal. yielded information on the presence of mixed ionic states of Sn2+ and Sn4+ in SQDs and further revealed that the no. of Sn2+ ions decreased at high temp. Band-edge shifts were estd. from XPS data. It was possible to shift the bandgap of annealed SQDs from UV to the visible wavelength region, which is likely to have a beneficial impact on many applications of optoelectronic devices.
  31. 31
    Villamagua, L.; Stashans, A.; Lee, P.; Liu, Y.; Liu, C.; Carini, M. Change in the electrical conductivity of SnO2 crystal from n-type to p-type conductivity. Chem. Phys. 2015, 452, 71– 77,  DOI: 10.1016/j.chemphys.2015.03.002
    Google Scholar
    There is no corresponding record for this reference.
  32. 32
    Zhu, B.; Cheng, B.; Zhang, L.; Yu, J. Review on DFT calculation of s-triazine-based carbon nitride. Carbon Energy 2019, 1, 32– 56,  DOI: 10.1002/cey2.1
    Google Scholar
    32
    Review on DFT calculation of s-triazine-based carbon nitride
    Zhu, Bicheng; Cheng, Bei; Zhang, Liuyang; Yu, Jiaguo
    Carbon Energy (2019), 1 (1), 32-56CODEN: CEANFS; ISSN:2637-9368. (John Wiley & Sons Australia, Ltd.)
    A review. To improve the photocatalytic performance of pristine photocatalysts, element doping, construction of composites and fabrication of novel nanostructures are recognized as universal modification methods. These methods have been exptl. verified to be effective in manifold photocatalytic application over various photocatalysts. D. functional theory (DFT) calcn. is a powerful and fundamental tool to pinpoint the intrinsic mechanism of the enhanced photocatalytic activity. And it holds the degree of precision ranging from atoms, mols. to unit cells. Herein, recent DFT calcn. research progress of modified s-triazine-based graphitic carbon nitride (g-C3N4) systems as photocatalysts is summarized. To specify, we collected information of doping site, formation energy, geometric, and electronic properties. We also discussed the synergistic effect of work function, Fermi level and band edge position on the built-in elec. field, transfer route of photogenerated charge carriers and photocatalytic mechanism (traditional type II or direct Z-scheme heterostructure). Moreover, we analyzed the geometric configuration, band structure, and stability of g-C3N4 nanocluster, nanoribbon, and nanotube. Finally, future perspective in the further theor. revelation of g-C3N4-based photocatalysts is proposed.
  33. 33
    Feng, J.; Jiang, T.; Han, Y.; Okoth, O. K.; Cheng, L.; Zhang, J. Construction of dual Z-scheme Bi2S3/Bi2O3/WO3 ternary film with enhanced visible light photoelectrocatalytic performance. Appl. Surf. Sci. 2020, 505, 144632  DOI: 10.1016/j.apsusc.2019.144632
    Google Scholar
    33
    Construction of dual Z-scheme Bi2S3/Bi2O3/WO3 ternary film with enhanced visible light photoelectrocatalytic performance
    Feng, Jun; Jiang, Tao; Han, Yingchun; Okoth, Otieno Kevin; Cheng, Ling; Zhang, Jingdong
    Applied Surface Science (2020), 505 (), 144632CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
    A dual Z-scheme Bi2S3/Bi2O3/WO3 ternary film was constructed via a controllable redn. of peroxotungstate by ethanol, calcination of Bi (NO3)3 and in situ anion exchange of Bi2O3 with sulfide. The as-prepd. composite film was characterized by SEM, X-ray diffraction and XPS. The UV-visible diffuse reflectance spectroscopic and photoluminescence studies indicated that the introduction of Bi2S3 in Bi2O3/WO3 film effectively improved the absorption of the film in the visible region and suppressed the recombination of photogenerated carriers. The photoelectrocatalytic activity of the Bi2S3/Bi2O3/WO3 film was evaluated by decoloration of Rhodamine B under visible light illumination. Compared with WO3 and Bi2O3/WO3 films, the Bi2S3/Bi2O3/WO3 film exhibited much higher degrdn. efficiency. Moreover, the enhanced visible light photoelectrocatalytic activity of the Bi2S3/Bi2O3/WO3 film was also demonstrated by efficient degrdn. of diclofenac. According to the reactive oxygen species detected by ESR, a dual Z-scheme system formed in the Bi2S3/Bi2O3/WO3 film was proposed, which offered a new approach to the construction of semiconducting composite film with high photoelectrocatalytic performance for pollutant removal.

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  • Abstract

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    Figure 1

    Figure 1. FT-IR spectra of (a) CNSnO-0 and (b) CNSnO-0.3.

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    Figure 2

    Figure 2. (A) Sn 3d, (B) C 1s, (C) N 1s, (D) wide XPS spectra of CNSnO-0.3.

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    Figure 3

    Figure 3. PL intensity of E2 (a) before photoirradiation, and after photoirradiation for 1 h with (b) CNSnO-0 and (c) CNSnO-0.3.

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    Figure 4

    Figure 4. (A) PL intensity of E2 after photoirradiation with CNSnO-0.3 for (a) 0, (b) 0.5, (c) 1.0, and (d) 2.0 h. (B) Integrated PL intensity of E2 as a function of photoirradiation time.

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    Figure 5

    Figure 5. Schematic band diagram of CNSnO composite photocatalyst to explain the photodegradation of E2.

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    Figure 6

    Figure 6. ESR spectra of radical adducts trapped by DMPO (a) before and (b) after photoirradiation.

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  • References

    This article references 33 other publications.

    1. 1
      Yilmaz, B.; Terekeci, H.; Sandal, S.; Kelestimur, F. Endocrine disrupting chemicals: exposure, effects on human health, mechanism of action, models for testing and strategies for prevention. Rev. Endocr. Metab. Disord. 2020, 21, 127– 147,  DOI: 10.1007/s11154-019-09521-z
      1
      Endocrine disrupting chemicals: exposure, effects on human health, mechanism of action, models for testing and strategies for prevention
      Yilmaz, Bayram; Terekeci, Hakan; Sandal, Suleyman; Kelestimur, Fahrettin
      Reviews in Endocrine & Metabolic Disorders (2020), 21 (1), 127-147CODEN: REMDCG; ISSN:1389-9155. (Springer)
      A review. Endocrine Disrupting Chems. (EDCs) are a global problem for environmental and human health. They are defined as "an exogenous chem., or mixt. of chems., that can interfere with any aspect of hormone action". It is estd. that there are about 1000 chems. with endocrine-acting properties. EDCs comprise pesticides, fungicides, industrial chems., plasticizers, nonylphenols, metals, pharmaceutical agents and phytoestrogens. Human exposure to EDCs mainly occurs by ingestion and to some extent by inhalation and dermal uptake. Most EDCs are lipophilic and bioaccumulate in the adipose tissue, thus they have a very long half-life in the body. It is difficult to assess the full impact of human exposure to EDCs because adverse effects develop latently and manifest at later ages, and in some people do not present. Some EDCs exert obesogenic effects that result in disturbance in energy homeostasis. Interference with hypothalamo-pituitary-thyroid and adrenal axes has also been reported. In this review, potential EDCs, their effects and mechanisms of action, epidemiol. studies to analyze their effects on human health, bio-detection and chem. identification methods, difficulties in extrapolating exptl. findings and studying endocrine disruptors in humans and recommendations for endocrinologists, individuals and policy makers will be discussed in view of the relevant literature.
    2. 2
      Lintelmann, J.; Katayama, A.; Kurihara, N.; Shore, L.; Wenzel, A. Endocrine disruptors in the environment (IUPAC Technical Report). Pure Appl. Chem. 2003, 75, 631– 681,  DOI: 10.1351/pac200375050631
      There is no corresponding record for this reference.
    3. 3
      Peng, Y.; Wang, J.; Wu, C. Determination of Endocrine Disruption Potential of Bisphenol A Alternatives in Food Contact Materials Using In Vitro Assays: State of the Art and Future Challenges. J. Agric. Food Chem. 2019, 67, 12613– 12625,  DOI: 10.1021/acs.jafc.9b01543
      3
      Determination of Endocrine Disruption Potential of Bisphenol A Alternatives in Food Contact Materials Using In Vitro Assays: State of the Art and Future Challenges
      Peng, Ying; Wang, Jieliang; Wu, Changqing
      Journal of Agricultural and Food Chemistry (2019), 67 (46), 12613-12625CODEN: JAFCAU; ISSN:0021-8561. (American Chemical Society)
      A review. Alternatives to Bisphenol A (BPA) are developed for food contact materials due to increasing evidence of exposure-correlated harmful effects of BPA. In vitro assays provide the fast, affordable, and mechanism insightful ways to screen endocrine disruption (ED) which is a major concern of new BPA alternatives. In this review, we summarize the safety and regulation information of the alternatives to BPA, review the state of the art of in vitro assays for ED evaluation, highlight their advantages and limitations, and discuss the challenges and future research needs. Our review shows that ligand binding, reporter gene, cell proliferation, and steroidogenesis are four commonly used in vitro assays to det. the ED at the response of receptor, gene transcription, and whole cell level. Major challenges are found from in vitro-in vivo translation and identification of ED chems. in polymers. More studies on these areas are needed in the future.
    4. 4
      Phillips, P. J.; Chalmers, A. T.; Gray, J. L.; Kolpin, D. W.; Foreman, W. T.; Wall, G. R. Combined Sewer Overflows: An Environmental Source of Hormones and Wastewater Micropollutants. Environ. Sci. Technol. 2012, 46, 5336– 5343,  DOI: 10.1021/es3001294
      4
      Combined Sewer Overflows: An Environmental Source of Hormones and Wastewater Micropollutants
      Phillips, P. J.; Chalmers, A. T.; Gray, J. L.; Kolpin, D. W.; Foreman, W. T.; Wall, G. R.
      Environmental Science & Technology (2012), 46 (10), 5336-5343CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
      Data collected at a wastewater treatment plant (WWTP) in Burlington, Vermont, serving 30,000 people assessed the relative contribution of combined sewer overflow (CSO) bypass flows and treated wastewater effluent to the steroid hormone and other wastewater micro-pollutant (WMP) load from a WWTP to a lake. Flow-weighted composite samples were collected for 13 mo at this WWTP from CSO bypass flows or treatment plant influent flows (n = 28) and treated effluent discharges (n = 22). Although CSO discharges represent 10% of the total annual water discharge (CSO plus treated plant effluent discharges) from the WWTP, CSO discharges contributed 40-90% of the annual hormones and WMP load with high (>90%) wastewater treatment removal efficiency. Compds. with low removal efficiencies (<90%) had <10% of their annual load contributed by CSO discharges. Estrogens, androgens, and WMP concns. were generally 10 times higher in CSO vs. treated wastewater discharges. Compd. concns. in CSO discharges generally decreased with increasing flow due to wastewater diln. by rainfall runoff. Hormone and many WMP concns. from treated wastewater could increase with increasing flow due to decreasing removal efficiency.
    5. 5
      Gross-Sorokin, M. Y.; Roast, S. D.; Brighty, G. C. Assessment of Feminization of Male Fish in English Rivers by the Environment Agency of England and Wales. Environ. Health Perspect. 2006, 114, 147– 151,  DOI: 10.1289/ehp.8068
      There is no corresponding record for this reference.
    6. 6
      Luo, J.; Zhang, S.; Sun, M.; Yang, L.; Luo, S.; Crittenden, J. C. A Critical Review on Energy Conversion and Environmental Remediation of Photocatalysts with Remodeling Crystal Lattice, Surface, and Interface. ACS Nano 2019, 13, 9811– 9840,  DOI: 10.1021/acsnano.9b03649
      6
      A critical review on energy conversion and environmental remediation of photocatalysts with remodeling crystal lattice, surface, and interface
      Luo, Jinming; Zhang, Shuqu; Sun, Meng; Yang, Lixia; Luo, Shenglian; Crittenden, John C.
      ACS Nano (2019), 13 (9), 9811-9840CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      A review. Solar energy is a renewable resource that can supply our energy needs in the long term. A semiconductor photocatalysis that is capable of utilizing solar energy has appealed to considerable interests for recent decades, owing to the ability to aim at environmental problems and produce renewal energy. Much effort has been put into the synthesis of a highly efficient semiconductor photocatalyst to promote its real application potential. Hence, we reviewed the most advanced methods and strategies in terms of (i) broadening the light absorption wavelengths, (ii) design of active reaction sites, and (iii) control of the electron-hole (e--h+) recombination, while these three processes could be influenced by remodeling the crystal lattice, surface, and interface. Addnl., we individually examd. their current applications in energy conversion (i.e., hydrogen evolution, CO2 redn., nitrogen fixation, and oriented synthesis) and environmental remediation (i.e., air purifn. and wastewater treatment). Overall, in this review, we particularly focused on advanced photocatalytic activity with simultaneous wastewater decontamination and energy conversion and further enriched the mechanism by proposing the electron flow and substance conversion. Finally, this review offers the prospects of semiconductor photocatalysts in the following three vital (distinct) aspects: (i) the large-scale prepn. of highly efficient photocatalysts, (ii) the development of sustainable photocatalysis systems, and (iii) the optimization of the photocatalytic process for practical application.
    7. 7
      UshaVipinachandran, V.; Rajendran, S.; Haroon, K. H. B.; Ashokan, I.; Mondal, A.; Bhunia, S. K. Detoxification of Endocrine Disruptors in Water Using Visible-LightActive Nanostructures: A Review. ACS Appl. Nano Mater. 2020, 3, 11659– 11687,  DOI: 10.1021/acsanm.0c02974
      There is no corresponding record for this reference.
    8. 8
      Zhu, Q.; Xu, Z.; Qiu, B.; Xing, M.; Zhang, J. Emerging Cocatalysts on g-C3N4 for Photocatalytic Hydrogen Evolution. Small 2021, 17, 2101070  DOI: 10.1002/smll.202101070
      8
      Emerging Cocatalysts on g-C3N4 for Photocatalytic Hydrogen Evolution
      Zhu, Qiaohong; Xu, Zehong; Qiu, Bocheng; Xing, Mingyang; Zhang, Jinlong
      Small (2021), 17 (40), 2101070CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)
      A review. Over the past few decades, graphitic carbon nitride (g-C3N4) has arisen much attention as a promising candidate for photocatalytic hydrogen evolution reaction (HER) owing to its low cost and visible light response ability. However, the unsatisfied HER performance originated from the strong charge recombination of g-C3N4 severely inhibits the further large-scale application of g-C3N4. In this case, the utilization of cocatalysts is a novel frontline in the g-C3N4-based photocatalytic systems due to the pos. effects of cocatalysts on suppressing charge carrier recombination, reducing the HER overpotential, and improving photocatalytic activity. This summarizes some recent advances about the high-performance cocatalysts based on g-C3N4 toward HER. Specifically, the functions, design principle, classification, modification strategies of cocatalysts, as well as their intrinsic mechanism for the enhanced photocatalytic HER activity are discussed here. Finally, the pivotal challenges and future developments of cocatalysts in the field of HER are further proposed.
    9. 9
      Yu, X.; Ng, S.; Putri, L. K.; Tan, L.; Mohamed, A. R.; Ong, W. Point-Defect Engineering: Leveraging Imperfections in Graphitic Carbon Nitride (g-C3N4) Photocatalysts toward Artificial Photosynthesis. Small 2021, 17, 2006851  DOI: 10.1002/smll.202006851
      9
      Point-defect engineering: Leveraging imperfections in graphitic carbon nitride (g-C3N4) photocatalysts toward artificial photosynthesis
      Yu, Xinnan; Ng, Sue-Faye; Putri, Lutfi Kurnianditia; Tan, Lling-Lling; Mohamed, Abdul Rahman; Ong, Wee-Jun
      Small (2021), 17 (48), 2006851CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)
      A review. Graphitic carbon nitride (g-C3N4) is a kind of ideal metal-free photocatalysts for artificial photosynthesis. At present, pristine g-C3N4 suffers from small sp. surface area, poor light absorption at longer wavelengths, low charge migration rate, and a high recombination rate of photogenerated electron-hole pairs, which significantly limit its performance. Among a myriad of modification strategies, point-defect engineering, namely tunable vacancies and dopant introduction, is capable of harnessing the superb structural, textural, optical, and electronic properties of g-C3N4 to acquire an ameliorated photocatalytic activity. In view of the burgeoning development in this pacey field, a timely review on the state-of-the-art advancement of point-defect engineering of g-C3N4 is of vital significance to advance the solar energy conversion. Particularly, insights into the intriguing roles of point defects, the synthesis, characterizations, and the systematic control of point defects, as well as the versatile application of defective g-C3N4-based nanomaterials toward photocatalytic water splitting, carbon dioxide redn. and nitrogen fixation will be presented in detail. Lastly, this review will conclude with a balanced perspective on the tech. and scientific hindrances and future prospects. Overall, it is envisioned that this review will open a new frontier to uncover novel functionalities of defective g-C3N4-based nanostructures in energy catalysis.
    10. 10
      Xiao, J.; Xie, Y.; Rabeah, J.; Bruckner, A.; Cao, H. Visible-Light Photocatalytic Ozonation Using Graphitic C3N4 Catalysts: A Hydroxyl Radical Manufacturer for Wastewater Treatment. Acc. Chem. Res. 2020, 53, 1024– 1033,  DOI: 10.1021/acs.accounts.9b00624
      10
      Visible-Light Photocatalytic Ozonation Using Graphitic C3N4 Catalysts: A Hydroxyl Radical Manufacturer for Wastewater Treatment
      Xiao, Jiadong; Xie, Yongbing; Rabeah, Jabor; Bruckner, Angelika; Cao, Hongbin
      Accounts of Chemical Research (2020), 53 (5), 1024-1033CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)
      Over the past 20 yr, photocatalytic ozonation (light/O3/photocatalyst), an independent advanced oxidn. process (AOP) proposed in 1996, demonstrated its robust oxidn. capacity and potential for practical wastewater treatment using sunlight and air (O3 source). However, its development is restricted by two major issues: a lack of break-through catalysts working under visible light (42-43% of sunlight energy) and ambiguous property-activity relationships; and unclear fundamental reasons underlying its high yield of OH-. This paper summarizes the substantial contributions to solve these issues, including: new-generation graphitic carbon nitride (g-C3N4) catalysts with excellent performance for photocatalytic ozonation under visible light; charge carrier transfer and reactive oxygen species (ROS) evolution mechanisms; property-activity relationships; and chem. and working stabilities of g-C3N4 catalysts. Based on these results, principles/directions for future catalyst design/optimization are discussed, and a new concept of integrating solar photocatalytic ozonation with catalytic ozonation in one facility for continuous wastewater treatment regardless of sunlight availability, is proposed. This begins from the finding that bulk/nanosheet/nanoporous g-C3N4 triggers a strong synergy between visible light (vis) and O3, causing efficient mineralization of a variety of org. pollutants. Using bulk g-C3N4 as an example, photocatalytic ozonation (vis/O3/g-C3N4) mineralized oxalic acid (model pollutant) at a rate 95.8 times higher than the sum of photocatalytic oxidn. (vis/O2/g-C3N4) and ozonation. To unravel this synergism, the authors developed a method based on in-situ ESR spectroscopy in conjunction with an online spin trapping method to monitor, under realistic aq. conditions, generation and transfer of photo-induced charge carriers and their reaction with dissolved O3/O2 to form ROS. The presence of only 2.1 mol percent O3 in the inlet O2 gas stream can trap 1-2 times more conduction band electrons than pure O2 and shifts the reaction pathway from inefficient three-electron redn. of O2 (O2 → O2- → HO2- → H2O2 → OH-) to more efficient one-electron redn. of O3 (O3 → O3- → HO3- → OH-), thereby increasing the yield of OH- by a factor of 17. Next, the band structure as a decisive factor for catalytic performance was confirmed and a new concept to resolve this relationship, involving the no. of reactive charge carriers, was established. An optimum balance between the no. and reducing ability of photo-induced electrons, which depends on the interplay between band gap and conduction band edge potential, is a key property for highly active g-C3N4 catalysts. It was demonstrated g-C3N4 is chem. stable toward O3 and O2-, but OH- can tear and oxidize its heptazine units to form cyameluric acid and further release NO3- to the aq. environment. Fortunately, OH- usually attacks wastewater org. pollutants in preference to g-C3N4, thereby preserving the g-C3N4 working stability and the steady operation of photocatalytic ozonation. This AOP, which serves as an in-situ OH- generator is of interest to a broad chem. world since OH- are active species for environmental applications and for org. synthesis, polymn., zeolite synthesis, and protein foot-printing.
    11. 11
      Guan, R.; Li, J.; Zhang, J.; Zhao, Z.; Wang, D.; Zhai, H.; Sun, D. Photocatalytic Performance and Mechanistic Research of ZnO/g-C3N4 on Degradation of Methyl Orange. ACS Omega 2019, 4, 20742– 20747,  DOI: 10.1021/acsomega.9b03129
      11
      Photocatalytic Performance and Mechanistic Research of ZnO/g-C3N4 on Degradation of Methyl Orange
      Guan, Renquan; Li, Jiaxin; Zhang, Junkai; Zhao, Zhao; Wang, Dandan; Zhai, Hongju; Sun, Dewu
      ACS Omega (2019), 4 (24), 20742-20747CODEN: ACSODF; ISSN:2470-1343. (American Chemical Society)
      Highly dispersed ZnO/g-C3N4 composites with different doping ratios of g-C3N4 were prepd. by a hydrothermal method. The prepn. method is simple and the energy consumption is low. The composite samples were used to degradate the Methyl orange soln. They all showed excellent photocatalytic activity and cycling stability. The optimal loading content of g-C3N4 was studied, and the mechanism of enhanced photocatalytic activity was studied. This study provides a promising photocatalytic material for the removal of org. pollutants.
    12. 12
      Gu, Y.; Li, S.; Li, M.; Wang, X.; Liu, Y.; Shi, K.; Bai, X.; Yao, Q.; Wu, Z.; Yao, H. Recent advances in g-C3N4-based photo-enzyme catalysts for degrading organic pollutants. RSC Adv. 2023, 13, 937– 947,  DOI: 10.1039/D2RA06994F
      There is no corresponding record for this reference.
    13. 13
      Liu, R.; Chen, Z.; Yao, Y.; Li, Y.; Cheema, W. A.; Wang, D.; Zhu, S. Recent advancements in g-C3N4-based photocatalysts for photocatalytic CO2 reduction: a mini review. RSC Adv. 2020, 10, 29408– 29418,  DOI: 10.1039/D0RA05779G
      13
      Recent advancements in g-C3N4-based photocatalysts for photocatalytic CO2 reduction: a mini review
      Liu Runlu; Yao Yao; Li Yao; Zhu Shenmin; Chen Zhixin; Cheema Waqas A; Wang Dawei
      RSC advances (2020), 10 (49), 29408-29418 ISSN:.
      Carbon dioxide (CO2) is a very important micro-molecular resource. Using CO2 captured from the atmosphere for high-output synthesis of chemicals as raw materials has great significance and potential for various industrial applications. Since the industrial revolution in the 18(th) century, manmade CO2 emission has increased by 45%, which negatively impacts the planetary climate by the so-called greenhouse effect. Therefore, high-efficiency photocatalysis and photocatalysts for CO2 conversion have become the most important challenges and milestones throughout the world. In consideration of this, various catalysts have been explored. Among these, graphitic carbon nitride (g-C3N4) as a semiconductor is emerging as a highly promising photocatalyst for removing CO2 from the atmosphere. Moreover, due to its excellent chemical stability and unique band structure, g-C3N4 has exhibited significant application potential for photocatalysis. This review summarizes the advancements that have been made in the synthesis and photocatalytic applications of g-C3N4-based catalysts for CO2 reduction in recent years and explains the future challenges and prospects in this vital area of research.
    14. 14
      Liebig, J. Uber einige stickstoff - verbindungen. Ann. Pharm. 1834, 10, 1– 47,  DOI: 10.1002/jlac.18340100102
      There is no corresponding record for this reference.
    15. 15
      Wang, X.; Maeda, K.; Thomas, A.; Takanabe, K.; Xin, G.; Carlsson, J. M.; Domen, K.; Antonietti, M. A metal-free polymeric photocatalyst for hydrogen production from water under visible light. Nat. Mater. 2009, 8, 76– 80,  DOI: 10.1038/nmat2317
      15
      A metal-free polymeric photocatalyst for hydrogen production from water under visible light
      Wang, Xinchen; Maeda, Kazuhiko; Thomas, Arne; Takanabe, Kazuhiro; Xin, Gang; Carlsson, Johan M.; Domen, Kazunari; Antonietti, Markus
      Nature Materials (2009), 8 (1), 76-80CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)
      The prodn. of hydrogen from water using a catalyst and solar energy is an ideal future energy source, independent of fossil reserves. For an economical use of water and solar energy, catalysts that are sufficiently efficient, stable, inexpensive and capable of harvesting light are required. Here, we show that an abundant material, polymeric carbon nitride, can produce hydrogen from water under visible-light irradn. in the presence of a sacrificial donor. Contrary to other conducting polymer semiconductors, carbon nitride is chem. and thermally stable and does not rely on complicated device manufg. The results represent an important first step towards photosynthesis in general where artificial conjugated polymer semiconductors can be used as energy transducers.
    16. 16
      Hassani, A.; Faraji, M.; Eghbali, P. Facile fabrication of mpg-C3N4/Ag/ZnO nanowires/Zn photocatalyst plates for photodegradation of dye pollutant. J. Photochem. Photobiol., A 2020, 400, 112665  DOI: 10.1016/j.jphotochem.2020.112665
      16
      Facile fabrication of mpg-C3N4/Ag/ZnO nanowires/Zn photocatalyst plates for photodegradation of dye pollutant
      Hassani, Aydin; Faraji, Masoud; Eghbali, Paria
      Journal of Photochemistry and Photobiology, A: Chemistry (2020), 400 (), 112665CODEN: JPPCEJ; ISSN:1010-6030. (Elsevier B.V.)
      Mpg-C3N4/Ag/ZnO NWs/Zn photocatalyst plates were fabricated through facile dip-coating process of silver and mesoporous graphitic carbon nitride onto zinc oxide nanowires previously formed by electrochem. anodizing of Zn plates. The structure, optical and electrochem. characterizations of the fabricated samples were investigated by XRD, FESEM, EDX, TEM, FTIR, BET, PL, UV-vis DRS, and EIS analyses. To evaluate the photocatalytic activity of the plates, the main key factors such as no. of photocatalyst plates, dye concn., initial pH, and reaction time for the degrdn. of Direct Orange 26 dye under UV light illumination were studied. The best photocatalytic efficiency of 94% was achieved using four photocatalyst plates, 10 mg/L DO26, and pH = 6 in 120 min of reaction time. The integration of the mpg-C3N4/Ag/ZnO NWs/Zn plates, adsorption, and photolysis inferred the existence of a synergy index of 5 for the degrdn. of target pollutant. In the presence of edetate disodium and ethanol, degrdn. efficiency of DO26 was remarkably dropped to 43.6% and 19.3% by the photocatalytic process resp., indicating the major role of h+ and -OH in the destruction of target mols. Fabrication of the mpg-C3N4/Ag/ZnO NWs/Zn plates is anticipated to be a rational design for photocatalytic degrdn. of various pollutants.
    17. 17
      Hassani, A.; Eghbali, P.; Metin, O. Sonocatalytic removal of methylene blue from water solution by cobalt ferrite/mesoporous graphitic carbon nitride (CoFe2O4/mpg-C3N4) nanocomposites: response surface methodology approach. Environ. Sci. Pollut. Res. Int. 2018, 25, 32140– 32155,  DOI: 10.1007/s11356-018-3151-3
      17
      Sonocatalytic removal of methylene blue from water solution by cobalt ferrite/mesoporous graphitic carbon nitride (CoFe2O4/mpg-C3N4) nanocomposites: response surface methodology approach
      Hassani Aydin; Eghbali Paria; Metin Onder
      Environmental science and pollution research international (2018), 25 (32), 32140-32155 ISSN:.
      In this study, cobalt ferrite/mesoporous graphitic carbon nitride (CoFe2O4/mpg-C3N4) nanocomposites were successfully synthesized by using a two-step protocol. Firstly, monodispersed CoFe2O4 nanoparticles (NPs) were synthesized via thermal decomposition of metal precursors in a hot surfactant solution and then they were assembled on mpg-C3N4 via a liquid phase self-assembly method. The sonocatalytic performance of as-synthesized CoFe2O4/mpg-C3N4 nanocomposites was evaluated on the methylene blue (MB) removal from water under ultrasonic irradiation. For this purpose, response surface methodology (RSM) based on central composite design (CCD) model was successfully utilized to optimize the MB removal over CoFe2O4/mpg-C3N4 nanocomposites. Analysis of variance (ANOVA) was applied to investigate the significance of the model. The results predicted by the model were obtained to be in reasonable agreement with the experimental data (R(2) = 0.969, adjusted R(2) = 0.942). Pareto analysis demonstrated that pH of the solution was the most effective parameter on the sonocatalytic removal of MB by CoFe2O4/mpg-C3N4 nanocomposites. The optimum catalyst dose, initial dye concentration, pH, and sonication time were set as 0.25 g L(-1), 8 mg L(-1), 8, and 45 min, respectively. The high removal efficiency of MB dye (92.81%) was obtained under optimal conditions. The trapping experiments were done by using edetate disodium, tert-butyl alcohol, and benzoquinone. Among the reactive radicals, (•)OH played a more important role than h(+) and [Formula: see text] in the MB dye removal process. Moreover, a proposed mechanism was also presented for the removal of MB in the presence of CoFe2O4/mpg-C3N4 nanocomposites under the optimized sonocatalytic conditions. Finally, a reusability test of the nanocomposites revealed a just 9.6% decrease in their removal efficiency after five consecutive runs.
    18. 18
      Hassani, A.; Krishnan, S.; Scaria, J.; Eghbali, P.; Nidheesh, P. V. Z-scheme photocatalysts for visible-light-driven pollutants degradation: A review on recent advancements. Curr. Opin. Solid State Mater. Sci. 2021, 25, 100941  DOI: 10.1016/j.cossms.2021.100941
      18
      Z-scheme photocatalysts for visible-light-driven pollutants degradation: A review on recent advancements
      Hassani, Aydin; Krishnan, Sukanya; Scaria, Jaimy; Eghbali, Paria; Nidheesh, P. V.
      Current Opinion in Solid State & Materials Science (2021), 25 (5), 100941CODEN: COSSFX; ISSN:1359-0286. (Elsevier Ltd.)
      A review. Harvesting solar energy for energy and environmental applications is an ever-fascinating field of research. Although semiconductor photocatalysis is the potential tool for recalcitrant degrdn., it still suffers from rapid recombination, inability to utilize visible light, and lower photocatalytic performance. Recently, the Z-scheme photocatalysts are becoming research hotspots for their strong redox ability, charge carrier sepn., and ability to exploit visible light. This review provides insights into the fundamental mechanism, synthesis strategies, and characterization techniques of Z-scheme photocatalysts. The recent advancements in their applications in visible-light-driven pollutants degrdn. are also reviewed.
    19. 19
      Ji, H.; Fan, Y.; Yan, J.; Xu, Y.; She, X.; Gu, J.; Fei, T.; Xu, H.; Li, H. Construction of SnO2/graphene-like g-C3N4 with enhanced visible light photocatalytic activity. RSC Adv. 2017, 7, 36101– 36111,  DOI: 10.1039/C7RA05830F
      19
      Construction of SnO2/graphene-like g-C3N4 with enhanced visible light photocatalytic activity
      Ji, Haiyan; Fan, Yamin; Yan, Jia; Xu, Yuanguo; She, Xiaojie; Gu, Jiemin; Fei, Ting; Xu, Hui; Li, Huaming
      RSC Advances (2017), 7 (57), 36101-36111CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)
      In this work, SnO2/graphene-like g-C3N4 (SnO2/GL-C3N4) composite photocatalysts with large surface areas and abundant coupling heterointerfaces were synthesized using a hydrothermal method. The as-prepd. photocatalysts exhibited distinctly manifested efficient visible light activities toward org. pollutant degrdn., demonstrating remarkable synergistic effects between SnO2 and graphene-like g-C3N4 (GL-C3N4). The 25 wt% SnO2/GL-C3N4 composite showed optimal photocatalytic activity under visible light irradn., which was almost 9 and 2.5 times as high as that of SnO2 and GL-C3N4, resp. In addn., the possible photocatalytic mechanism of rhodamine B (RhB) degrdn. by SnO2/GL-C3N4 under visible light was also discussed in detail. Moreover, this work would provide a facile way for the fabrication of novel two dimension/two dimension (2D/2D) GL-C3N4-based photocatalysts with high and stable performance for pollutant degrdn.
    20. 20
      Putri, L. K.; Ng, B.; Ong, W.; Lee, H. W.; Chang, W. S.; Chai, S. Engineering nanoscale p–n junction via the synergetic dual-doping of p-type boron-doped graphene hybridized with n-type oxygen-doped carbon nitride for enhanced photocatalytic hydrogen evolution. J. Mater. Chem. A 2018, 6, 3181– 3194,  DOI: 10.1039/C7TA09723A
      20
      Engineering nanoscale p-n junction via the synergetic dual-doping of p-type boron-doped graphene hybridized with n-type oxygen-doped carbon nitride for enhanced photocatalytic hydrogen evolution
      Putri, Lutfi Kurnianditia; Ng, Boon-Junn; Ong, Wee-Jun; Lee, Hing Wah; Chang, Wei Sea; Chai, Siang-Piao
      Journal of Materials Chemistry A: Materials for Energy and Sustainability (2018), 6 (7), 3181-3194CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)
      In this study, an effective 2D-2D heterojunction composite was formulated by hybridizing oxygen doped graphitic carbon nitride (O-gC3N4) with boron doped reduced graphene oxide (B-rGO) using a combined sonication-assisted electrostatic self-assembly approach. Pristine gC3N4 possesses a neg. surface charge, which later transforms into a pos. charge upon doping with elemental oxygen. This reversal of surface charge, which occurred on top of doping, established the opportune electrostatic coupling of pos. charged O-gC3N4 and neg. charged B-rGO. Moreover, the concerted dual doping of both O-gC3N4 and B-rGO, which exhibited n-type and p-type cond., resp., allowed the construction of a nanoscale p-n heterojunction system at the interface, warranting a more effective and rapid charge sepn. and in turn bolstering the photocatalytic hydrogen performance. In particular, the optimal loading content of B-rGO was 2% with a corresponding H2 prodn. rate of 1639 μmol g-1 after 6 h, which is a remarkable 4-fold photocatalytic improvement as compared to that of O-gC3N4. In brief, this study highlights that the dual doping of both gC3N4 and rGO and their hybridization present a powerful strategy to increase the photoactivity of the composite since doping could remarkably modulate their interaction at the heterointerface.
    21. 21
      Fina, F.; Callear, S. K.; Carins, G. M.; Irvine, J. T. S. Structural Investigation of Graphitic Carbon Nitride via XRD and Neutron Diffraction. Chem. Mater. 2015, 27, 2612– 2618,  DOI: 10.1021/acs.chemmater.5b00411
      21
      Structural Investigation of Graphitic Carbon Nitride via XRD and Neutron Diffraction
      Fina, Federica; Callear, Samantha K.; Carins, George M.; Irvine, John T. S.
      Chemistry of Materials (2015), 27 (7), 2612-2618CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
      Graphitic carbon nitride (g-C3N4) has, since 2009, attracted great attention for its activity as a visible-light-active photocatalyst for hydrogen evolution. Since it was synthesized in 1834, g-C3N4 has been extensively studied both catalytically and structurally. Although its 2D structure seems to have been solved, its 3D crystal structure has not yet been confirmed. This study attempts to solve the 3D structure of graphitic carbon nitride by means of X-ray diffraction and of neutron scattering. Initially, various structural models are considered and their XRD patterns compared to the measured one. After selecting possible candidates as g-C3N4 structure, neutron scattering is employed to identify the best model that describes the 3D structure of graphitic carbon nitride. Parallel chains of tri-s-triazine units organized in layers with an A-B stacking motif are found to describe the structure of the synthesized graphitic carbon nitride well. A misalignment of the layers is favorable because of the decreased π-π repulsive interlayer interactions.
    22. 22
      Akgul, F. A.; Gumus, C.; Er, A. O.; Farha, A. H.; Akgul, G.; Ufuktepe, Y.; Liu, Z. Structural and electronic properties of SnO2. J. Alloys Compd. 2013, 579, 50– 56,  DOI: 10.1016/j.jallcom.2013.05.057
      22
      Structural and electronic properties of SnO2
      Akgul, Funda Aksoy; Gumus, Cebrail; Er, Ali O.; Farha, Ashraf H.; Akgul, Guvenc; Ufuktepe, Yuksel; Liu, Zhi
      Journal of Alloys and Compounds (2013), 579 (), 50-56CODEN: JALCEU; ISSN:0925-8388. (Elsevier B.V.)
      Highly transparent polycryst. thin film of SnO2 (tin dioxide) was deposited using a simple and low cost spray pyrolysis method. The film was prepd. from an aq. soln. of tin tetrachloride (stannic chloride) onto glass substrates at 400°. A range of diagnostic techniques including x-ray diffraction (XRD), UV-visible absorption, at. force microscopy (AFM), SEM, and synchrotron-based XPS were used to investigate structural, optical, and electronic properties of the resulting film. Deposited film was found to be polycryst. A mixt. of SnO and SnO2 phases was obsd. The av. crystallite size of ∼21.3 nm for SnO2 was calcd. by Rietveld method using XRD data. The oxidn. states of the SnO2 thin film were confirmed by the shape anal. of corresponding XPS O 1s, Sn 3d, and Sn 4d peaks using the decompn. procedure. The anal. of the XPS core level peaks showed that the chem. component is non-stoichiometric and the ratio of oxygen to tin (O/Sn) is 1.85 which is slightly under stoichiometry.
    23. 23
      Kumar, P.; Vahidzadeh, E.; Thakur, U. K.; Kar, P.; Alam, K. M.; Goswami, A.; Mahdi, N.; Cui, K.; Bernard, G. M.; Michaelis, V. K.; Shankar, K. C3N5: A Low Bandgap Semiconductor Containing an Azo-Linked Carbon Nitride Framework for Photocatalytic, Photovoltaic and Adsorbent Applications. J. Am. Chem. Soc. 2019, 141, 5415– 5436,  DOI: 10.1021/jacs.9b00144
      23
      C3N5: A Low Bandgap Semiconductor Containing an Azo-Linked Carbon Nitride Framework for Photocatalytic, Photovoltaic and Adsorbent Applications
      Kumar, Pawan; Vahidzadeh, Ehsan; Thakur, Ujwal K.; Kar, Piyush; Alam, Kazi M.; Goswami, Ankur; Mahdi, Najia; Cui, Kai; Bernard, Guy M.; Michaelis, Vladimir K.; Shankar, Karthik
      Journal of the American Chemical Society (2019), 141 (13), 5415-5436CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Modification of carbon nitride based polymeric 2D materials for tailoring their optical, electronic and chem. properties for various applications has gained significant interest. The present report demonstrates the synthesis of a novel modified carbon nitride framework with a remarkable 3:5 C:N stoichiometry (C3N5) and an electronic bandgap of 1.76 eV, by thermal deammoniation of melem hydrazine precursor. Characterization revealed that in C3N5 polymer, two s-heptazine units are bridged together with azo linkage, which constitutes an entirely new and different bonding fashion from g-C3N4 where three heptazine units are linked together with tertiary nitrogen. Extended conjugation due to overlap of azo nitrogens and increased electron d. on heptazine nucleus due to the arom. π network of heptazine units lead to an upward shift of the valence band max. resulting in bandgap redn. down to 1.76 eV. XRD, He-ion imaging, HR-TEM, EELS, PL, fluorescence life time imaging, Raman, FTIR, TGA, KPFM etc. clearly show that the properties of C3N5 are distinct from pristine carbon nitride (g-C3N4). When used as an electron transport layer (ETL) in MAPbBr3 based halide perovskite solar cells, C3N5 outperformed g-C3N4, in particular generating an open circuit photovoltage as high as 1.3 V, while C3N5 blended with MAxFA1-xPb(I0.85Br0.15)3 perovskite active layer achieved a photoconversion efficiency (PCE) ≤ 16.7 %. C3N5 was also shown to be an effective visible light sensitizer for TiO2 photoanodes in photoelectrochem. water splitting. Due to its electron-rich character, the C3N5 material displayed instantaneous adsorption of methylene blue from aq. soln. reaching complete equil. within 10 min, which is significantly faster than pristine g-C3N4 and other carbon- based materials. C3N5 coupled with plasmonic silver nanocubes promotes plasmon-exciton co-induced surface catalytic reactions reaching completion at much low laser intensity (1.0 mW) than g-C3N4 which showed sluggish performance even at high laser power (10.0 mW). The relatively narrow bandgap and 2D structure of C3N5 make it an interesting air-stable and temp.-resistant semiconductor for optoelectronic applications while its electron- rich character and intra-sheet cavity make it an attractive supramol. adsorbent for environmental applications.
    24. 24
      Wang, H.; Duan, A.; Mao, J.; Che, B.; Wang, W.; Ma, M.; Wang, Xuedong. Effects of Ionic Liquids on Fluorescence Characteristics of 17α- and 17β-estradiol. J. Fluoresc. 2013, 23, 103– 113,  DOI: 10.1007/s10895-012-1123-4
      There is no corresponding record for this reference.
    25. 25
      Ohko, Y.; Iuchi, K.; Niwa, C.; Tatsuma, T.; Nakashima, T.; Iguchi, T.; Kubota, Y.; Fujishima, A. 17β-Estradiol Degradation by TiO2 Photocatalysis as a Means of Reducing Estrogenic Activity. Environ. Sci. Technol. 2002, 36, 4175– 4181,  DOI: 10.1021/es011500a
      25
      17β-Estradiol Degradation by TiO2 Photocatalysis as a Means of Reducing Estrogenic Activity
      Ohko, Yoshihisa; Iuchi, Ken-ichiro; Niwa, Chisa; Tatsuma, Tetsu; Nakashima, Tetsuto; Iguchi, Taisen; Kubota, Yoshinobu; Fujishima, Akira
      Environmental Science and Technology (2002), 36 (19), 4175-4181CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
      The degrdn. of 17β-estradiol (E2) in water by TiO2 photocatalysis was investigated; concurrently, the estrogenic activity of the treated water was evaluated during the photocatalytic reactions by an estrogen screening assay. As a result, 10-6M E2 was totally mineralized to CO2 in 1.0 g TiO2/L suspension under UV irradn. for 3 h. 10ε-17β-Dihydroxy-1,4-estradien-3-one and testosterone-like species were elucidated as intermediate products by gas chromatog./mass spectrometry (GC/MS) anal. The mechanisms of E2 degrdn. by TiO2 photocatalysis were discussed not only exptl. but also theor. by calcg. the frontier electron densities of the E2 mol. On the basis of the results obtained, it was concluded that the phenol moiety of the E2 mol., one of the essential functional groups to interact with the estrogen receptor, should be the starting point of the photocatalytic oxidn. of E2. This means that the estrogenic activity should be almost lost concurrently with the initiation of the photocatalytic degrdn. Actually, the estrogenic activities of the intermediate products were negligible. TiO2 photocatalysis could be applied to water treatment to effectively remove natural and synthetic estrogens without producing biol. active intermediary products.
    26. 26
      Zhao, Y.; Hu, H.; Jin, W. Transformation of Oxidation Products and Reduction of Estrogenic Activity of 17β-Estradiol by a Heterogeneous Photo-Fenton Reaction. Environ. Sci. Technol. 2008, 42, 5277– 5284,  DOI: 10.1021/es703253q
      26
      Transformation of Oxidation Products and Reduction of Estrogenic Activity of 17β-Estradiol by a Heterogeneous Photo-Fenton Reaction
      Zhao, Yaping; Hu, Jiangyong; Jin, Wei
      Environmental Science & Technology (2008), 42 (14), 5277-5284CODEN: ESTHAG; ISSN:0013-936X. (American Chemical Society)
      A novel photo-Fenton catalyst, α-FeOOH loaded resin (α-FeOOHR), was synthesized and evaluated through transformation of a steroidal endocrine disrupting compds. (EDC), 17β-estradiol (E2), under weak UV irradn. in the presence of H2O2. E2 photodegrdn. intermediates elucidated in detail by GC/MS and LC/MS/MS analyses and detailed reaction pathways are proposed. A yeast-based estrogen screen for E2 and its photodegrdn. intermediates was performed to measure the redn. of estrogenic activity in different water matrixes during the heterogeneous photo-Fenton process. The results showed that α-FeOOHR not only degraded E2 but also removed the estrogenic activity originating from E2, its degrdn. intermediates, and its products. However, the water matrix present in drinking water may impact estrogenic activity redn. The results are important to evaluate the ability of photo-Fenton advanced oxidn. processes in reducing EDCs and their assocd. estrogenicity from drinking water.
    27. 27
      Mitamura, K.; Narukawa, H.; Mizuguchi, T.; Shimada, K. Degradation of estrogen conjugates using titanium dioxide as a photocatalyst. Anal. Sci. 2004, 20, 3– 4,  DOI: 10.2116/analsci.20.3
      There is no corresponding record for this reference.
    28. 28
      Zhu, D.; Zhou, Q. Nitrogen doped g-C3N4 with the extremely narrow band gap for excellent photocatalytic activities under visible light. Appl. Catal., B 2021, 281, 119474  DOI: 10.1016/j.apcatb.2020.119474
      28
      Nitrogen doped g-C3N4 with the extremely narrow band gap for excellent photocatalytic activities under visible light
      Zhu, Dandan; Zhou, Qixing
      Applied Catalysis, B: Environmental (2021), 281 (), 119474CODEN: ACBEE3; ISSN:0926-3373. (Elsevier B.V.)
      In this work, nitrogen doped g-C3N4 (NCN) with the extremely narrow band gap was prepd. and applied for the photodegrdn. of phenols. Expts. and DFT (the d. functional theory) computation identified that N-doping introduced in the g-C3N4 matrix by substituting C atoms. DFT, PL (photoluminescence) spectra, optical property characteristic and PEC (photoelectrochem.) indicated that NCN possess extremely narrow band gap, efficient photogenerated carrier sepn. and the charge transfer, which enhanced the absorption of visible light and further promoted the photocatalytic activity. As a result, NCN(2:2) showed about twice higher photodegrdn. efficiencies and 3 times rate const. than pristine g-C3N4. The radical trapping expts. showed that •O2- radical and h+ served as crucial active species during the whole photodegrdn. reaction. This work can provide a strategy to enhance the photocatalytic activity of photocatalysts via introduce foreign atoms in matrix.
    29. 29
      Reddy, C. V.; Babu, B.; Vattikuti, S. V. P.; Ravikumar, R. V. S. S. N.; Shim, J. Structural and optical properties of vanadium doped SnO2 nanoparticles with high photocatalytic activities. J. Lumin. 2016, 179, 26– 34,  DOI: 10.1016/j.jlumin.2016.06.036
      29
      Structural and optical properties of vanadium doped SnO2 nanoparticles with high photocatalytic activities
      Reddy, Ch. Venkata; Babu, B.; Vattikuti, S. V. Prabhakar; Ravikumar, R. V. S. S. N.; Shim, Jaesool
      Journal of Luminescence (2016), 179 (), 26-34CODEN: JLUMA8; ISSN:0022-2313. (Elsevier B.V.)
      Vanadium (0.01, 0.03 and 0.05 mol%) doped SnO2 nanoparticles have been synthesized using combustion synthesis method. The as-prepd. nanoparticles were characterized using various measurements such as XRD, SEM with EDS, HRTEM, Raman spectroscopy, optical, PL, XPS and FT-IR techniques. The crystal structure and av. particle sizes of the prepd. nanoparticles were confirmed from the XRD. The av. cryst. particle sizes were decreased by increasing the vanadium dopant concn. The presence of vanadium as V4+ species in the host lattice was confirmed by XPS. The band gap energies were decreased by increasing dopant concn. The 0.05 mol% doped sample showed higher photocatalytic activity than undoped, V-1 and V-3 in decompg. rhodamine B (RhB) under UV light irradn. The Raman and IR spectra confirm the fundamental vibration of SnO2 host mols.
    30. 30
      Babu, B.; Reddy, I. N.; Yoo, K.; Kim, D.; Shim, J. Bandgap tuning and XPS study of SnO2 quantum dots. Mater. Lett. 2018, 221, 211– 215,  DOI: 10.1016/j.matlet.2018.03.107
      30
      Bandgap tuning and XPS study of SnO2 quantum dots
      Babu, Bathula; Neelakanta Reddy, I.; Yoo, Kisoo; Kim, Dongseob; Shim, Jaesool
      Materials Letters (2018), 221 (), 211-215CODEN: MLETDJ; ISSN:0167-577X. (Elsevier B.V.)
      The authors investigated the influence of annealing temp. on ultra-small SnO2 quantum dots (SQDs) prepd. by a simple chem. redn. process. The structural and optical properties of annealed SQDs were systematically studied by different techniques. The results show that the crystallinity and av. crystallite size of annealed SQDs increased gradually with annealing temp. The av. crystallite size was maintained below 10 nm even for high annealing temps. XPS peak fitting anal. yielded information on the presence of mixed ionic states of Sn2+ and Sn4+ in SQDs and further revealed that the no. of Sn2+ ions decreased at high temp. Band-edge shifts were estd. from XPS data. It was possible to shift the bandgap of annealed SQDs from UV to the visible wavelength region, which is likely to have a beneficial impact on many applications of optoelectronic devices.
    31. 31
      Villamagua, L.; Stashans, A.; Lee, P.; Liu, Y.; Liu, C.; Carini, M. Change in the electrical conductivity of SnO2 crystal from n-type to p-type conductivity. Chem. Phys. 2015, 452, 71– 77,  DOI: 10.1016/j.chemphys.2015.03.002
      There is no corresponding record for this reference.
    32. 32
      Zhu, B.; Cheng, B.; Zhang, L.; Yu, J. Review on DFT calculation of s-triazine-based carbon nitride. Carbon Energy 2019, 1, 32– 56,  DOI: 10.1002/cey2.1
      32
      Review on DFT calculation of s-triazine-based carbon nitride
      Zhu, Bicheng; Cheng, Bei; Zhang, Liuyang; Yu, Jiaguo
      Carbon Energy (2019), 1 (1), 32-56CODEN: CEANFS; ISSN:2637-9368. (John Wiley & Sons Australia, Ltd.)
      A review. To improve the photocatalytic performance of pristine photocatalysts, element doping, construction of composites and fabrication of novel nanostructures are recognized as universal modification methods. These methods have been exptl. verified to be effective in manifold photocatalytic application over various photocatalysts. D. functional theory (DFT) calcn. is a powerful and fundamental tool to pinpoint the intrinsic mechanism of the enhanced photocatalytic activity. And it holds the degree of precision ranging from atoms, mols. to unit cells. Herein, recent DFT calcn. research progress of modified s-triazine-based graphitic carbon nitride (g-C3N4) systems as photocatalysts is summarized. To specify, we collected information of doping site, formation energy, geometric, and electronic properties. We also discussed the synergistic effect of work function, Fermi level and band edge position on the built-in elec. field, transfer route of photogenerated charge carriers and photocatalytic mechanism (traditional type II or direct Z-scheme heterostructure). Moreover, we analyzed the geometric configuration, band structure, and stability of g-C3N4 nanocluster, nanoribbon, and nanotube. Finally, future perspective in the further theor. revelation of g-C3N4-based photocatalysts is proposed.
    33. 33
      Feng, J.; Jiang, T.; Han, Y.; Okoth, O. K.; Cheng, L.; Zhang, J. Construction of dual Z-scheme Bi2S3/Bi2O3/WO3 ternary film with enhanced visible light photoelectrocatalytic performance. Appl. Surf. Sci. 2020, 505, 144632  DOI: 10.1016/j.apsusc.2019.144632
      33
      Construction of dual Z-scheme Bi2S3/Bi2O3/WO3 ternary film with enhanced visible light photoelectrocatalytic performance
      Feng, Jun; Jiang, Tao; Han, Yingchun; Okoth, Otieno Kevin; Cheng, Ling; Zhang, Jingdong
      Applied Surface Science (2020), 505 (), 144632CODEN: ASUSEE; ISSN:0169-4332. (Elsevier B.V.)
      A dual Z-scheme Bi2S3/Bi2O3/WO3 ternary film was constructed via a controllable redn. of peroxotungstate by ethanol, calcination of Bi (NO3)3 and in situ anion exchange of Bi2O3 with sulfide. The as-prepd. composite film was characterized by SEM, X-ray diffraction and XPS. The UV-visible diffuse reflectance spectroscopic and photoluminescence studies indicated that the introduction of Bi2S3 in Bi2O3/WO3 film effectively improved the absorption of the film in the visible region and suppressed the recombination of photogenerated carriers. The photoelectrocatalytic activity of the Bi2S3/Bi2O3/WO3 film was evaluated by decoloration of Rhodamine B under visible light illumination. Compared with WO3 and Bi2O3/WO3 films, the Bi2S3/Bi2O3/WO3 film exhibited much higher degrdn. efficiency. Moreover, the enhanced visible light photoelectrocatalytic activity of the Bi2S3/Bi2O3/WO3 film was also demonstrated by efficient degrdn. of diclofenac. According to the reactive oxygen species detected by ESR, a dual Z-scheme system formed in the Bi2S3/Bi2O3/WO3 film was proposed, which offered a new approach to the construction of semiconducting composite film with high photoelectrocatalytic performance for pollutant removal.

  • Supporting Information

    Supporting Information

    The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.4c03390.

    • Figure S1. Crystal structure of g-C3N4, S2. Oxidative degradation process of 17β-estradiol (E2), S3. XRD patterns of (a) CNSnO-0, (b) CNSnO-0.3 and (c) SnO2 crystal, S4. XRD pattern of g-C3N4 prepared from melamine, S5. (A) Sn 3d XPS spectrum of SnO2 powder sample. (B) C 1s and (C) O 1s XPS spectra of CNSnO-0.3, S6. FE-SEM images of (A) CNSnO-0 and (B) CNSnO-0.3, S7. TEM images of CNSnO-0.3, S8. EDS spectrum of CNSnO-0.3. N, O and Sn mapping images of CNSnO-0.3, S9. The figure with the vertical axis of Figure 4B replotted on a logarithmic scale, S10. Cycling performance of CNSnO-0.6, S11. Tauc plot of CNSnO-0, S12. Mott–Schottky plot of CNSnO-0.3, S13. PL spectra of (a) CNSnO-0 and (b) CNSnO-0.3. Table S1. XPS peak position and peak height of CNSnO-0.3 and SnO2 powder sample, S2. BET specific surface area of CNSnO samples, S3. ζ Potential of CNSnO-0 and −0.3 (PDF)


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