Insights into the CO catalytic oxidation mechanism over MnO₂-CeO₂ (111) surface: Experimental and DFT calculation

Research on the catalytic oxidation of carbon monoxide (CO) over non-precious metal catalysts to release carbon dioxide (CO₂) was gaining increasing attention. In this study, experiments and density functional theory (DFT) calculation were employed to elucidate the mechanism of CO catalytic oxidation over MnO₂-CeO₂ (111) catalysts. The results revealed that the CO catalytic oxidation over MnO₂-CeO₂ (111) catalysts followed the MvK mechanism. The catalytic oxidation of CO involved the initial adsorption of CO and the subsequent formation of carbonate and formate intermediates, leading to three plausible catalytic oxidation pathways. Based on experimental and theoretical results, three reaction pathways on MnO₂-CeO₂(111) catalysts were finally derived. The adsorption capacity, activation energy barrier, and reaction heat for catalytic oxidation were estimated via DFT methods. This study mainly revealed three reaction pathways on the MnO₂-CeO₂ (111) catalyst through experiments and DFT methods. Among these, carbon monoxide reacts directly with lattice oxygen or forms carbonate intermediates, both of which were relatively easy to achieve. The formation of HCOO* intermediates, however, was comparatively difficult.