Support effects on the nucleation, growth, and morphology of gold nano-clusters

The nucleation, growth, and morphology of gold (Au) clusters on an irreducible oxide (SiO2), highly reduced TiOx (x ∼ 1), and less reduced TiOx (x ∼ 2) were investigated by scanning tunneling microscopy (STM) with the goal of understanding the relationship between the nucleation, growth, and morphology of Au clusters and the reducibility of the oxide support. Au clusters show preferential nucleation and growth on a TiOx surface compared to a SiO2 surface. In addition, higher densities of Au clusters were found on highly reduced TiOx, suggesting that reduced Ti sites play a role as an active site for the nucleation and growth of Au clusters.