CuC(O) Interfaces Deliver Remarkable Selectivity and Stability for CO Reduction to C Products at Industrial Current Density of 500 mA cm.

The electrocatalytic CO reduction reaction (CO RR) is an attractive technology for CO valorization and high-density electrical energy storage. Achieving a high selectivity to C products, especially ethylene, during CO RR at high current densities (>500 mA cm ) is a prized goal of current research, though remains technically very challenging. Herein, it is demonstrated that the surface and interfacial structures of Cu catalysts, and the solid-gas-liquid interfaces on gas-diffusion electrode (GDE) in CO reduction flow cells can be modulated to allow efficient CO RR to C products. This approach uses the in situ electrochemical reduction of a CuO nanosheet/graphene oxide dots (CuOC(O)) hybrid. Owing to abundant CuOC interfaces in the CuOC(O) hybrid, the CuO nanosheets are topologically and selectively transformed into metallic Cu nanosheets exposing Cu(100) facets, Cu(110) facets, Cu[n(100) × (110)] step sites, and Cu /Cu interfaces during the electroreduction step, the faradaic efficiencie (FE) to C hydrocarbons was reached as high as 77.4% (FE  ≈ 60%) at 500 mA cm . In situ infrared spectroscopy and DFT simulations demonstrate that abundant Cu species and Cu /Cu interfaces in the reduced CuOC(O) catalyst improve the adsorption and surface coverage of *CO on the Cu catalyst, thus facilitating CC coupling reactions.