Factors influencing structure and catalytic activity of Au/Ce1−xZrxO2 catalysts in CO oxidation

Abstract

The Au/Ce1−xZrxO2 (x=0, 0.25, 0.5, 0.75, 1) catalysts were synthesized by the direct anionic exchange (DAE) method, characterized by BET, SEM–EDS, XRD, TPR-CO, HRTEM, AAS, ToF-SIMS and tested in CO oxidation. The correlations between structural, redox and catalytic properties of Au/Ce1−xZrxO2 catalysts prepared using different synthesis procedures have been studied. The poisoning effect of residual chlorine on their catalytic performance was found. The agglomeration of Au particles during the calcination step in the presence of residual chlorine was observed. Its removal through the washing treatment both inhibited the sintering process and led to the increase in activity of the studied systems. The sequence of increasing activity was followed by the sequence of increasing reducibility of the catalysts. This shows the role of the support redox properties in the creation of the catalytic performance of supported Au nanoparticles in CO oxidation.