Robust and Moisture-Resistant Nanostructured Ag−Cu/CeMnZrO x Catalysts for CO Oxidation

Abstract Catalysts capable of retaining performance under harsh conditions, including the presence of water vapor, feature high durability and reproducibility of properties. Here, the nanostructured Ag−Cu/CeMnZrOx catalysts are obtained by varying the introduction methods (co-impregnation of the support or impregnation of the pre-reduced Cu-containing support) and the ratio of Ag and Cu (total metal loading is no more than 2 wt %). The Ag introduction by impregnation of pre-reduced Cu-CeMnZrOx leads to a significant enhancement in the catalyst defect structure and an increase in the surface reactivity. A higher catalytic activity in CO oxidation is found at the Ag/Cu ratio of 1.5:0.5 (Ea = 29 kJ/mol) and is associated with the synergistic action of the active sites of the catalyst surface. Over eight consecutive cycles, it undergoes initial surface reoxidation and then stabilizes. Wet conditions show a positive effect on CO conversion owing to enhanced oxygen mobility in its defective solid solutions. The distribution characteristics of Ag and Cu depending on the method of their introduction, the possibility of forming Ag−Cu sites, and the cooperation of the sites with the active sites of the CeMnZrOx support are discussed. The results obtained can be used to develop robust and durable nanostructured oxidation catalysts.