Geometric and electronic structure of Au on $Au/CeO_{2}$ catalysts during the CO oxidation:Deactivation by reaction induced particle growth

Changes of the geometric and electronic structure of gold on Au/CeO2 catalysts induced by different pre-treatments (oxidative and reductive) and the CO oxidation reaction at 80°C have been determined by XANES and EXAFS. The results demonstrate that the active species during reaction is metallic Au, and that there is a reaction induced Au particle growth. This is true for each of the different pre-treatment procedures, although these result in significantly different Au particle sizes as well as different Au oxidation states. Correlations to the catalysts activity give a detailed insight into the origin of deactivation on Au/CeO2 under present reaction conditions, in particular on the role of the Au particle size during reaction