Tailoring Solvent-Mediated CO Reservoirs at Heterointerfaces for Enhanced Electrochemical CO-to-CH Conversion.

Transforming waste CO into value-added fuels and chemicals, while simultaneously enabling renewable electricity storage, presents a viable strategy for achieving a sustainable energy economy. However, efficient conversion to C products remains challenging, primarily due to the low CO concentration at the catalyst surface in aqueous environments. Herein, we addressed this issue by designing CuO-MgO catalysts with abundant nanointerfaces serving as effective CO reservoirs under aqueous conditions. Ab initio molecular dynamics simulations demonstrated that these interfaces substantially enhanced the CO stabilization at the surface, effectively inhibiting their displacement by interfacial water molecules. This localized CO enrichment facilitated C-C coupling kinetics and selectively promoted the formation of target products. Building on these findings, we synthesized a model catalyst featuring abundant CuO-MgO nanointerfaces and evaluated its performance in aqueous media. Remarkably, flowing electrolyzer tests demonstrated a Faradaic efficiency of 67% for ethylene at a current density of ∼ 240 mA·cm. Subsequent mechanistic investigations combining spectroscopy experiments and theoretical calculation simulations demonstrated that the surface-enriched CO enhanced the CO* coverage at the Cu active sites, thereby promoting ethylene production through facilitated C-C coupling. This study pioneers the rational design of heterogeneous catalysts for selective CORR toward value-added chemicals with potential applications extending to diverse electrocatalytic processes.