The effect of Ag and CeO2 distribution on SBA-15 surface on the activity of Ag-CeO2/SBA-15 catalysts in CO and methanol oxidation

摘要

The series of catalysts representing the mesoporous ordered silica SBA-15 with supported silver or silver and ceria nanoparticles were synthesized by incipient wetness impregnation, characterized by the low-temperature N-2 adsorption, XRD, TEM HR, TPR-H-2 methods, and tested in the low-temperature CO oxidation and total oxidation of methanol. It was found that two types of silver particles are formed: small particles (<3 nm) inside the pores of the SBA-15 and larger particles (3-15 nm) on the external surface of SBA-15. High activity of the prepared catalyst in oxidation of CO and methanol is attributed to both small sizes of silver particles and the Ag-CeO2 interaction. The distribution of both silver and ceria on the SBA-15 surface determines their interaction and, hence, enhances the catalytic activity in oxidative reactions due to the cooperation of active oxidative sites of silver and ceria at the Ag-CeO2 interface.