Insight into Copper Oxide-Tin Oxide Catalysts for the Catalytic Oxidation of Carbon Monoxide: Identification of Active Copper Species and a Reaction Mechanism

Herein, we report the high activity of CuO-SnO 2 catalysts for the catalytic oxidation of CO. In particular, SnCu30 shows the highest activity and a high water resistance. If we compare the XRD, X-ray absorption fine structure, and H 2 temperature-programmed reduction results of SnCu30 before and after HNO 3 treatment, we find the existence of three kinds of Cu species in the catalyst, that is, highly dispersed CuO, bulk CuO, and Cu incorporated in the SnO 2 lattice. The highly dispersed CuO and the surface lattice oxygen species are the active sites for the catalytic oxidation of CO. We used X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared Fourier transform spectroscopy to confirm the existence of Cu + species on the surface of the CuO-SnO 2 catalysts, which can provide the adsorption sites for CO. Our results show that the reaction pathways of the catalytic oxidation of CO over the CuO-SnO 2 catalysts follow the Mars–van Krevelen model. Graphical When oxides oxidize : CuO-SnO 2 catalysts show a high activity and water resistance for the catalytic oxidation of CO. Three Cu species are identified on the catalysts, and the highly dispersed Cu, as well as the surface lattice oxygen, is the active site for the catalytic oxidation of CO. The reaction mechanism follows the Mars–van Krevelen model.