Influences of doping and thermal stability on the catalytic performance of CuO/Ce20M1Ox (M = Zr, Cr, Mn, Fe, Co, Sn) catalysts for NO reduction by CO

Abstract

For NO reduction by CO with CuO/Ce₂₀M₁O_x (M = Zr, Cr, Mn, Fe, Co, Sn) catalysts, the results imply that for fresh catalysts, the doping variable valence M^x+ is more conducive to an increase in the oxygen vacancies, the content of unsaturated metal cations on the surface, and the reduction capacity. The Cu/CeMn and Cu/CeSn samples exhibited better potential; after aging, the samples doped with Cr⁶⁺, Mn⁴⁺, and Co³⁺ had poor physicochemical properties, but doping with Zr⁴⁺, Fe³⁺, and Sn⁴⁺ resulted in better thermal stability. The Cu/CeSn sample exhibited the best catalytic properties and thermal stability, which are closely related to its structure retention, oxygen vacancies, the content of the surface chemical adsorption oxygen and surface unsaturated metal cation, and reduction capacity, whether it is fresh or aged. Finally, in order to further understand the interaction between the CO and NO probe molecules with the catalyst surface, a possible reaction mechanism for NO reduction by CO on a Cu/CeSn catalyst is tentatively proposed.