Engineering cooperative oxide interfaces to regulate carbon dioxide adsorption and electrocatalytic selectivity

Carbon dioxide electrocatalysts are conventionally designed to optimize reactant adsorption and conversion at the same catalytic surface. Here, we introduce an alternative design concept in which these functions are distributed across a nanoscale oxide interface. A nanocoating is integrated with zinc oxide nanorods to create interfacial sites that favour carbon dioxide adsorption while preserving the underlying zinc oxide centers responsible for its electrochemical conversion. Structural, surface, and in-situ spectroscopic characterisation reveals that the nanocoating preserves the zinc oxide crystal structure and nanorod morphology while modifying the local surface environment and promoting oxygen-vacancy formation. Density functional theory calculations provide an atomistic picture of this interface, identifying favourable interfacial aluminum‑oxygen configurations that strengthen carbon dioxide binding and support increased carbon dioxide availability near the zinc oxide active centers. Importantly, this interfacial regulation translates into a marked shift in the competition between carbon dioxide reduction and hydrogen evolution: whereas bare zinc oxide progressively loses carbon monoxide selectivity at increasingly cathodic potentials, the modified interface sustains carbon monoxide formation while suppressing the competing hydrogen evolution reaction. These findings establish an electrocatalyst design principle in which molecular adsorption and catalytic conversion are promoted by different but cooperating components of the same nanoscale architecture. Rather than altering the bulk catalyst to optimize its intrinsic activity, engineering the local reaction environment redirects competing electrochemical pathways towards carbon dioxide conversion, providing a general strategy for controlling electrocatalytic selectivity through functional differentiation at catalytic interfaces.