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

Graphical abstract Highlights • Defective LaNi 0.5 M 0.5 O 3 perovskites are synthesized by improved sol–gel method. • Doping M ions into LaNiO 3 leads to modified activity of NO + CO reaction. • The LaNi 0.5 Cu 0.5 O 3 catalyst exhibits optimized N 2 selectivity. • The improvement is attributed to surface amorphous CuO and oxygen vacancy. • The catalytic mechanism of LaNi 0.5 Cu 0.5 O 3 conforms to L-H mechanism. Abstract Catalytic removal of NO by CO has been studied over a series of LaNi 0.5 M 0.5 O 3 (M = Co, Mn, Cu) perovskite oxide catalysts were synthetized via an improved sol–gel method. The effects of M-doped on physicochemical properties of LaNiO 3 were systemic characterized by XRD, BET, SEM, ICP-AES, XPS, H 2 -TPR and O 2 -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 LaNi 0.5 Cu 0.5 O 3 possessed optimized catalytic performance, especially superior N 2 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 N 2 O. Hence, adsorbed CO can fast react with N and O at lower temperature, afterwards N 2 O was converted to N 2 fleetly, leading the improvement of activity/selectivity toward NO + CO reaction. [ABSTRACT FROM AUTHOR]