When Gold Is Not Noble: Nanoscale Gold Catalysts
While inert as bulk material, nanoscale gold particles dispersed on oxide supports exhibit a remarkable catalytic activity. Temperature-programmed reaction studies of the catalyzed combustion of CO on size-selected small monodispersed Au n ( n ≤ 20) gold clusters supported on magnesia, and first-principle simulations, reveal the microscopic origins of the observed unusual catalytic activity, with Au 8 found to be the smallest catalytically active size. Partial electron transfer from the surface to the gold cluster and oxygen-vacancy F-center defects are shown to play an essential role in the activation of nanosize gold clusters as catalysts for the combustion reaction.