Activation of Au nanoparticles on oxide surfaces: reaction of SO2 with Au/MgO(1 0 0)

Photoemission, thermal desorption spectroscopy and density-functional calculations were used to study the chemistry of SO2 on Au nanoparticles supported on MgO(1 0 0). The heat of adsorption of the molecule on the Au nanoparticles is ∼15 kcal/mol compared to 8 kcal for SO2 on Au(1 1 1). corner sites in the Au nanoparticles are responsible for this difference in reactivity. The dissociation of SO2 on Au/MgO(1 0 0) is very limited due to weak Au ↔ MgO interactions. A comparison of the behavior of SO2 on Au/MgO(1 0 0) and Au/TiO2(1 1 0) shows how important can be the effects of the oxide support for the activation of Au nanoparticles.