Hydrocarbon Formation from Syngas with In-Operando Monitoring of Cobalt- and Manganese-Based (pre)Catalysts Using X-ray Diffraction

Two-layered metal oxides (LiCoO2 and cobalt-doped KnMnO2, n < 1) were explored as precatalysts for nanoconfined cobalt-based Fischer–Tropsch catalysts for conversion of syngas (CO and H2) to hydrocarbons. Ex situ, in situ, and PDF XRD analyses are presented. Based on in situ XRD analysis, LiCoO2 underwent reduction to predominantly cubic and hexagonal phases of cobalt metal. Reaction with syngas resulted in the generation of carbon, cobalt carbide, and lithium carbonate, in addition to the metallic cobalt phases. In the case of cobalt-doped birnessite, catalyst activation converted the birnessite phase to manganite and the cobalt to elemental cobalt, along with similar lithium and carbon phases. Conversion of syngas to C1 through C7 products was observed. The best conversions were observed for the LiCoO2 precursor catalyst, with generally a low olefin-to-paraffin ratio. While the conversions for the cobalt-doped birnessite precatalyst were generally lower, with lower chain lengths (up to C5), these catalysts gave a strikingly high olefin-to-paraffin ratio: in the best case, greater than 20:1.


BET
The BET adsorption isotherm in Figure S4 was identified as type II isotherm, a characteristic of a non-porous or microporous solid.The shape was the result of unrestricted monolayermultilayer adsorption up to capillary condensation.The total surface area of the sample material was 348 m 2 /g.The volume specific surface area of 72.75 m 2 /cm 3 indicated that the sample can be identified as nanomaterial according to the official EC recommendation as the value of VSSA was higher than 60 m 2 cm -3 .

Figure S3 .
Figure S3.Cobalt region of the XPS of LiCoO 2

Figure S6 .
Figure S6.(a) BET isotherm (b) multipoint BET for LiCoO 2 for the surface area analysis.

Figure S7 .
Figure S7.(a) BET isotherm (b) multipoint BET for cobalt-doped birnessite for the surface area analysis.

Figure S9 .
Figure S9.Refinement plot of the all-cobalt catalyst before the activation.The result shows the sample contains 89.2 wt% of LiCoO 2 and 10.8 wt% of Li 2 CO 3 .R wp = 3.8%.λ = 0.24105 Å. Background scattering from the fused quartz capillary has been subtracted.

Figure S10 .
Figure S10.Evolution of phases and their abundances in the activated all-cobalt catalyst sample in the FTS catalysis process with increasing temperature (top panel), and the evolution of cobalt-bearing phases and their relative abundance (bottom panel).

Figure S11 .
Figure S11.Evolution of phases and their abundances in the activated Co-doped birnessite catalyst sample in the FTS catalysis process with increasing temperature (top panel), and the evolution of cobalt-bearing phases and their relative abundance (bottom panel).

Figure S12 .
Figure S12.Refinement plot of the activated all-cobalt catalyst at 25 °C before the FTS process.The plot is only the low angle region of the whole refinement that extended to 2θ max of 31.8°, which equals to d min of 0.44 Å. R wp = 12.6%.λ = 0.24105 Å.

Figure S13 .
Figure S13.Refinement plot of the all-cobalt catalyst at 350 °C when the Co 2 C phase peaked.The plot is only the low angle region of the whole refinement that extended to 2θ max of 31.8°, which equals to d min of 0.44 Å. R wp = 8.3%.λ = 0.24105 Å.

Figure S14 .
Figure S14.Refinement plot of the all-cobalt catalyst at 500 °C when carbon accumulation is clearly seen.The plot is only the low angle region of the whole refinement that extended to 2θ max of 31.8°, which equals to d min of 0.44 Å. R wp = 11.5%.λ = 0.24105 Å.

Figure S15 .
Figure S15.Refinement plot of the activated Co-doped MnO catalyst at 25 °C before the FTS process.The plot is only the low angle region of the whole refinement that extended to 2θ max of 33°, which equals to d min of 0.42 Å. R wp = 7.5%.λ = 0.24105 Å.

Figure S16 .
Figure S16.Refinement plot of the Co-doped MnO catalyst at 400 °C when the Co 2 C phase peaked.The plot is only the low angle region of the whole refinement that extended to 2θ max of 33°, which equals to d min of 0.42 Å. R wp = 5.9%.λ = 0.24105 Å.

Figure S17 .
Figure S17.Refinement plot of the Co-doped MnO catalyst at 500 °C when carbon accumulation is clearly seen.The plot is only the low angle region of the whole refinement that extended to 2θ max of 33°, which equals to d min of 0.42 Å. R wp = 6.0%.λ = 0.24105 Å.

Figure S18 .
Figure S18.In-situ PDF showing phase evolution of LiCoO 2 precatalyst during activation and catalysis.The plot shows that activation proceeds to reduce LiCoO 2 to the predominantly Co phase within the first few sequences, and that the catalyst remains predominantly in this form throughout the remainder of the catalysis.

Figure S19 .
Figure S19.In-situ PDF showing phase evolution of cobalt-doped birnessite precatalyst during activation and catalysis.The plot shows that activation proceeds to reduce the precatalyst to the predominantly MnO and Co phases within the first few sequences, and that the catalyst remains predominantly in this form throughout the remainder of the catalysis.

Table S3 .
The phase abundance results (wt%) from the Rietveld refinement for the activated Co-doped birnessite sample.The data are plotted in FigureS10.Unfilled boxes mean the phases were not observed at those temperatures.

Table S4 .
Crystallite size estimates for the two metallic Co phases from Rietveld Refinement

Table S5 .
Refinement R wp values in percentage