Catalytically active states of Ru(0001) catalyst in CO oxidation reaction

• Published in: Journal of catalysis Vol. 239; no. 2; pp. 354 - 361
• Main Authors: Blume, R., Hävecker, M., Zafeiratos, S., Teschner, D., Kleimenov, E., Knop-Gericke, A., Schlögl, R., Barinov, A., Dudin, P., Kiskinova, M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 25.04.2006; Elsevier; Elsevier BV
• Subjects: Catalysis; Catalytically active states; Chemistry; CO oxidation; Exact sciences and technology; General and physical chemistry; High pressure XPS; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; High pressure XPS; Ru; CO oxidation; Catalytically active states; Catalytic reaction; Ruthenium; Crystal face; Transition metal; X ray; High pressure; Heterogeneous catalysis; Photoelectron spectrometry; Oxidation; Carbon monoxide; Platinoid; Catalyst
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2006.02.019

Identifying the composition of the catalytically active state of metal catalysts under dynamic operating conditions is of particular importance for oxidation catalysis. Here we report new insights into the chemical identity of different catalytically active states formed on a Ru(0001) catalyst during CO oxidation at various reaction temperatures. The changes in the surface composition of the Ru catalyst and the CO 2 yield under varying reaction conditions in the 10 −4 – 10 −1 mbar pressure range were followed in situ by synchrotron-based high-pressure X-ray photoelectron spectroscopy and mass spectroscopy. The results reveal that the catalytic activity of a few layers thick surface oxide without well-defined stoichiometry and structure is comparable with that of the stoichiometric RuO 2(110) phase. This surface oxide forms under reaction conditions when RuO 2 formation is kinetically hindered and can coexist with RuO 2 in wide temperature and pressure ranges.