The Cu(210)/ZnO Interface: The Operando Active Sites for Industrial Water-Gas Shift Catalysis

Abstract

Copper nanoparticles (NPs) supported on a ZnO substrate represent a textbook catalytic system for industrial applications. However, the atomic identity of their active sites remains obscured by the “pressure gap” between surface science and industrial catalysis. Using multiscale structure reconstruction modeling, we elucidate the energetic driving forces behind the shape evolution of Cu NPs, demonstrating that high CO chemical potentials under realistic industrial pressures (P_CO > 1 bar) induce a drastic in situ morphological restructuring. Crucially, this structural evolution remains highly robust under operando water-gas shift reaction (WGSR) conditions with coexisting CO and H₂O, where the Cu NPs preferentially expose previously overlooked open (210) facets, while the conventionally emphasized stepped or Cu(111) vicinal facets virtually vanish. Integrating density functional calculations with microkinetic simulations, we reveal that the self-generated Cu(210)/ZnO interfaces exhibit enhanced catalytic activity for the WGSR, profoundly reducing the reaction barriers of the rate-determining steps while accelerating the overall turnover kinetics. Our simulated turnover frequencies quantitatively align with experimental benchmarks, establishing the Cu(210)/ZnO interface, rather than traditional models, as the authentic active site. These findings shift the paradigm of Cu/ZnO catalysis from static surface models to environment-adaptive interfacial evolution under realistic working conditions.