Monolithic porous CuO/CeO2 nanorod composites prepared by dealloying for CO catalytic oxidation

Abstract

Synergistic interaction is an improved and unique catalytic property that is superior to the catalytic effect of a counterpart when two or more materials are combined to form a composite. Copper-ceria composites are proven to be high-active materials for various catalytic reactions owing to the synergistic interaction between Cu species and CeO2 that endowed them exceptional redox and catalytic performances. In this study, CuO/CeO2 nanorod composites were fabricated by a facile alloying-dealloying strategy along with calcination for CO oxidation. The obtained CuO/CeO2 displayed a porous framework structure in which highly dispersed CuO were in-situ loaded on the surfaces of CeO2 nanorods. XRD studies revealed the incorporation of Cu ions into the CeO2 lattice, resulting in the formation of abundant oxygen vacancies in the composites as evidenced by XPS results. The CuO/CeO2 nanorod catalyst prepared from Al85Ce10Cu5 alloy calcined at 500 °C exhibited high catalytic activity for CO oxidation, which can realize 98% CO conversion as low as 160 °C owing to the strong synergistic interaction between dispersed CuO and CeO2 nanorods. Kinetic studies indicated a possible reaction mechanism over CuO/CeO2 catalyst: chemisorbed CO on reductive Cu+ species reacted with lattice oxygen activated in the oxygen vacancies of CeO2 nanorods.