Restructuring-Induced Activity SiO2-Supported Large Au Nanoparticles in Low-Temperature CO Oxidation

Large An nanoparticles with an average size of approximately 10 nm supported on inert SiO2 become active in low-temperature CO oxidation after the addition of NaNO3. The catalyst structures have been characterized in detail by X-ray diffraction. X-ray photoelectron spectroscopy, transmission electron microscopy, and X-ray absorption spectroscopy. The NaNO3 additive in Au/SiO2 catalysts does not lead to the formation of fine An nanoparticles, which are generally considered to be inevitable in low-temperature CO oxidation catalyzed by gold, nor does it alter the electronic structure of Au. The NaNO3-induced restructuring of large Au nanoparticles was proposed to create low-coordinated Au sites on the surface capable of catalyzing low-temperature CO oxidation. These results experimentally prove that the activity of supported Au nanoparticles in low-temperature CO oxidation could solely arise from their geometric structure, which greatly deepens the fundamental understandings of Au nanocatalysis.