Critical Role of Cu Nanoparticle-Loaded Cu(100) Surface Structures on Structured Copper-Based Catalysts in Boosting Ethanol Generation in CO₂ Electroreduction

Presently, realizing high ethanol selectivity in CO2 electroreduction remains challenging due to difficult C–C coupling and fierce product competition. In this work, we report an innovative approach for improving the efficiency of Cu-based electrocatalysts in ethanol generation from electrocatalytic CO2 reduction using a crystal plane modification strategy. These novel Cu-based electrocatalysts were fabricated by electrochemically activating three-dimensional (3D) flower-like CuO micro/nanostructures grown in situ on copper foils and modifying with surfactants. It was demonstrated that the fabricated Cu-based electrocatalyst featured a predominantly exposed Cu(100) surface loaded with high-density Cu nanoparticles (NPs). The optimal Cu-based electrocatalyst displayed considerably improved CO2 electroreduction performance, with a Faraday efficiency of 37.9% for ethanol and a maximum Faraday efficiency of 68.0% for C2+ products at −1.4 V vs RHE in an H-cell, accompanied by a high current density of 69.9 mA·cm–2, much better than the particulate Cu-based electrocatalyst. It was unveiled that the Cu(100)-rich surface of nanoscale petals with abundant under-coordinated copper atoms from CuNPs was conducive to the formation and stabilization of key *CH3CHO and *OC2H5 intermediates, thereby promoting ethanol generation. This study highlighted the critical role of CuNP-loaded Cu(100) surface structures on structured Cu-based electrocatalysts in enhancing ethanol production for the CO2 electroreduction process.