Cu increases oxygen vacancies in MnO2 to improve chlorine resistance in CO oxidation reaction

The catalytic oxidation of carbon monoxide (CO) by manganese oxide catalysts has always been a research hotspot. In complex sintering flue gas environments, chlorinated volatile organic compounds (CVOCs) with high toxicity, volatility, and recalcitrance have a significant impact on the CO oxidation activity of catalysts. In this investigation, dichloromethane (DCM) was used as a model pollutant to study the effect of CVOCs on CO catalytic oxidation reaction for the first time. The preparation of Cu0.25/MnO2 using the oxalic acid chelationassisted hydrothermal method showed the best CO removal efficiency and chlorine resistance. Cu promoted the generation of oxygen vacancies by enhancing electron transfer, which was beneficial for slowing down the adsorption of chlorine species on active sites. The introduction of Cu lowers the desorption temperature of HCl and inhibit the reversible adsorption of chlorine species. Through the use of in-situ DRIFT and other physical and chemical techniques, it was found that the mechanism of catalyst deactivation is staged. (1) Short-term deactivation: DCM adsorbed on oxygen vacancies, temporarily covering the active sites. (2) Long-term deactivation: DCM decomposed to produce chlorine species, which form stable Cl metal species with the metal. The mechanism by which copper doping enhanced the chlorine resistance of catalysts has been clarified, providing new insights into improving the chlorine resistance of catalysts.