Cu/Cu2O interface-modulated two-stage reduction of Cu2O under methanol

Abstract

Abstract Interfaces play crucial roles in catalysis. Beyond catalyst/support interfaces, formation of metal/metal-oxide (M/MO) interfaces during redox reactions and their impact on catalytic reaction mechanisms is poorly understood. Combining in situ Environmental TEM with quantitative statistical analyses and DFT calculations, we observe two-stage reduction dynamics of epitaxial Cu2O/Cu(110) model catalysts under methanol, which is modulated by the Cu2O||Cu junction structure. Anisotropic layer-by-layer reduction occurs at Cu2O island (110) side facets when the junction interfaces are along (100). In contrast, when the Cu2O||Cu interfaces are along (110), isotropic reduction at both top and side facets of Cu2O islands is observed. Anisotropic-to-isotropic transitions are supported by stochastic statistical analyses of island size evolution kinetics and DFT simulations showing MeOH adsorption energetics that favor defect sites at Cu2O||Cu(100) junctions. Our findings contribute to a deeper understanding of M/MO interfacial dynamics during catalytic reactions, providing new insights towards catalyst design and interface engineering.