Role of promoting oxide morphology dictating the activity of Au/SiO2 catalyst in CO oxidation

Abstract

The interfacial interaction of gold nanoparticles deposited on either model SiO2/Si(100) or high surface area amorphous or mesoporous silica with minute amounts of promoter oxide like "active" FeOx, TiO2 and CeO2 has been discussed. The role of the active oxide, its contribution to the perimeter along the gold nanoparticles has been interpreted. The oxide may invoke electronic interaction and simultaneously the defect structure of oxides likely has a key issue in the formation and stabilization of very small Au particles. The activity of the Au/oxide perimeter depends not only on the size of the Au particles, but also on the size and morphology of the oxide component (likely amorphous structure) regardless of whether it is supporting Au nanoparticles or decorating them. The activity in CO oxidation over Au catalysts is strongly affected by the length of the Au/"active" oxide perimeter which is regarded as the "active interface". The longer length of the perimeter is evidenced by the enhanced CO oxidation activity.