Low-temperature CO oxidation over CuO-CeO2/SiO2 catalysts: Effect of CeO2 content and carrier porosity

The effects of CeO2 contents and silica carrier porosity with their pore diameters ranging from 5.2 nm to 12.5 nm of CuO-CeO2/SiO2 catalysts in CO oxidation were investigated. The catalysts were characterized by N-2 adsorption/desorption at low temperature, X-ray diffraction (XRD), temperature-programmed reduction by H-2 (H-2-TPR), oxygen temperature programmed desorption (O-2-TPD) and X-ray photoelectron spectroscopy (XPS). The results suggested that, the ceria content and the porosity of SiO2 carrier possessed great impacts on the structures and catalytic performances of CuO-CeO2/SiO2 catalysts. When appropriate content of CeO2 (Ce content <= 8 wt%) was added, the catalytic activity was greatly enhanced. In the catalyst supported on silica carrier with larger pore diameter, higher dispersion of CuO was observed, better agglomeration-resistant capacity was displayed and more lattice oxygen could be found, thus the CuO-CeO2 supported on Si-1 showed higher catalytic activity for low-temperature CO oxidation.