Self-Inhibition\nPhenomena in Cu<sub>3</sub>Pt Oxidation\nby CO<sub>2</sub>

This study investigates the oxidation behavior of Cu<sub>3</sub>Pt(100) in CO<sub>2</sub> using a combination of ambient-pressure\nX-ray photoelectron spectroscopy, mass spectroscopy, and density functional\ntheory modeling. Our in situ measurements reveal the simultaneous\noxidation and reduction of Cu<sub>2</sub>O due to the opposing effects\nof atomic oxygen and CO generated from dissociative CO<sub>2</sub> adsorption, leading to a dynamic equilibrium state of simultaneously\noccurring redox reactions. Complementary atomistic calculations elucidate\nthe inhibitory effects of subsurface Pt enrichment and the counteracting\nroles of CO<sub>2</sub> and CO in surface oxidation and reduction.\nThese results provide mechanistic insights into the dissociative pathway\nof CO<sub>2</sub> molecules and dynamic evolution of surface composition\nand reactivity of Cu-based alloy catalysts in CO<sub>2</sub>-rich\nenvironments, with broader implications for tuning gas–surface\nreactions by manipulating gas reactants or solid surface composition.