CO Oxidation on Au<i>_n</i>/TiO₂ Catalysts Produced by Size-Selected Cluster Deposition

Abstract

Planar model catalysts were prepared by deposition of size-selected gold clusters containing up to seven atoms on rutile TiO2 (110). Molecular oxygen is observed to bind inefficiently to the surface, probably at oxygen vacancies, and some oxygen also appears to bind to the gold clusters. Stable CO binding is observed atop gold for catalysts prepared by Au and Au2 deposition, but not for larger Aun. CO oxidation activity is strongly dependent on cluster size, with Au7-prepared samples >50 times more reactive than samples prepared by Au or Au2 deposition