Photoemission Spectroscopy Study of Cu/CeO2 Systems: Cu/CeO2 Nanosized Catalyst and CeO2(111)/Cu(111) Inverse Model Catalyst

J. Phys. Chem. C, 112 (10), 3751 -3758, 2008. 10.1021/jp077739g S1932-7447(07)07739-4
Web Release Date: February 14, 2008

Photoemission Spectroscopy Study of Cu/CeO₂ Systems: Cu/CeO₂ Nanosized Catalyst and CeO₂(111)/Cu(111) Inverse Model Catalyst

Vladimír Matolín,* Libor Sedlek, Iva Matolínov, Frantiek utara, Tom Skla, Betislav míd, Jií Libra, Vclav Nehasil, and Kevin C. Prince

Charles University, Faculty of Mathematics and Physics, Department of Surface and Plasma Science, V Holeovikch 2, 18000 Prague 8, Czech Republic, and Sincrotrone Trieste, Strada Statale 14, km 163.5, 34012 Basovizza-Trieste, Italy

Received: September 26, 2007

In Final Form: December 17, 2007

Abstract:

Cerium oxide films equivalent to 2 ML of CeO₂ were grown at 520 K in an oxygen atmosphere on a clean Cu(111) substrate in order to prepare a model catalytic system. This "inverse model catalyst" was characterized by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) of core levels, and resonant photoelectron spectroscopy (RPES) of the valence band. Samples annealed at 770 K exhibited a LEED pattern corresponding to the (1.5 × 1.5) CeO₂(111)/Cu(111) structure that can be interpreted as formation of a flat, well-ordered cerium oxide overlayer aligned with the principal crystallographic axes of the substrate. The model catalytic system corresponds well to a copper-loaded ceria nanopowder catalyst that exhibits growth of Cu(111) film structure on CeO₂(111) planes. Lowering of the CO oxidation temperature due to the Cu loading is explained by CO adsorption on copper in the vicinity of highly active ceria planes providing oxygen for the reaction.

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