Catalytic removal NO by CO over LaNi0.5M0.5O3 (M = Co, Mn, Cu) perovskite oxide catalysts: Tune surface chemical composition to improve N2 selectivity

Abstract

Catalytic removal of NO by CO has been studied over a series of LaNi0.5M0.5O3 (M = Co, Mn, Cu) perovskite oxide catalysts were synthetized via an improved sol–gel method. The effects of M-doped on physicochemical properties of LaNiO3 were systemic characterized by XRD, BET, SEM, ICP-AES, XPS, H2-TPR and O2-TPD techniques. The possible catalytic mechanism for NO + CO model reaction was also tentatively proposed with the help of the in situ DRIFTS technique. The M-doped samples remained pure perovskite structure and exhibited modified activity, among which the LaNi0.5Cu0.5O3 possessed optimized catalytic performance, especially superior N2 selectivity. It is confirmed that the amorphous CuO highly dispersed on Cu-doped defective perovskite oxide, the reduction of Cu2+ to Cu+ is vital for the chemisorption of CO, a large amount of oxygen vacancies accelerated the dissociation of NO and N2O. Hence, adsorbed CO can fast react with N and O at lower temperature, afterwards N2O was converted to N2 fleetly, leading the improvement of activity/selectivity toward NO + CO reaction.