Self-Inhibition Phenomena in Cu₃Pt Oxidation by CO₂

This study investigates the oxidation behavior of Cu₃Pt(100) in CO₂ using a combination of ambient-pressure X-ray photoelectron spectroscopy, mass spectroscopy, and density functional theory modeling. Our in situ measurements reveal the simultaneous oxidation and reduction of Cu₂O due to the opposing effects of atomic oxygen and CO generated from dissociative CO₂ adsorption, leading to a dynamic equilibrium state of simultaneously occurring redox reactions. Complementary atomistic calculations elucidate the inhibitory effects of subsurface Pt enrichment and the counteracting roles of CO₂ and CO in surface oxidation and reduction. These results provide mechanistic insights into the dissociative pathway of CO₂ molecules and dynamic evolution of surface composition and reactivity of Cu-based alloy catalysts in CO₂-rich environments, with broader implications for tuning gas-surface reactions by manipulating gas reactants or solid surface composition.