Cu-C(O) Interfaces Deliver Remarkable Selectivity and Stability for CO₂ Reduction to C₂₊ Products at Industrial Current Density of 500 mA cm^-2

The electrocatalytic CO₂ reduction reaction (CO₂RR) is an attractive technology for CO₂ valorization and high-density electrical energy storage. Achieving a high selectivity to C₂₊ products, especially ethylene, during CO₂RR at high current densities (>500 mA cm^-2) 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 CO₂ reduction flow cells can be modulated to allow efficient CO₂RR to C₂₊ 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) x (110)] step sites, and Cu⁺/Cu⁰ interfaces during the electroreduction step, -the faradaic efficiencie (FE) to C₂₊ hydrocarbons was reached as high as 77.4% (FE_ethylene ≈ to 60%) at 500 mA cm^-2 . In situ infrared spectroscopy and DFT simulations demonstrate that abundant Cu⁺ species and Cu⁰/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. © 2023 Wiley-VCH GmbH