Insights into SnO2 Nanoparticles Supported on Fibrous Mesoporous Silica for CO Catalytic Oxidation

A large surface area dendritic mesoporous silica material (KCC-1) was successfully synthesized and used as a support to confine SnO2 nanoparticles (NPs). Owing to the large specific surface area and abundant mesoporous structure of dendritic KCC-1, the SnO2 NPs were highly dispersed, resulting in significantly improved CO catalytic oxidation activity. The obtained Sn-x/KCC-1 catalysts (x represents the mass fraction of SnO2 loading) exhibited excellent CO catalytic activity, with the Sn7@KCC-1 catalyst achieving 90% CO conversion at about 175 degrees C. The SnO2 NPs on the KCC-1 surface in a highly dispersed amorphous form, as well as the excellent interaction between SnO2 NPs and KCC-1, positively contributed to the catalytic removal process of CO on the catalyst surface. The CO catalytic removal pathway was established through a combination of in situ diffuse reflectance infrared transform spectroscopy and density-functional theory calculations, revealing the sequential steps: (1) CO -> CO3ads2-, (2) CO3ads2- -> CO2free+SnOx-1, (3) SnOx-1+O-2 -> SnOx+1. This study provides valuable insights into the design of high-efficiency non-precious metal catalysts for CO catalytic oxidation catalysts with high efficiency.