Surface/interface reconstruction in-situ on Cu2O catalysts with high exponential facets toward enhanced electrocatalysis CO2 reduction to C2+ products

A concept of surface/interface construction in-situ to design Cu 2 O/Cu catalysts on Cu 2 O nanostructures with highly active facets as highly efficient CO 2 RR catalysts have been demonstrated. • 1. Cu 2 O catalysts with active facets and morphologies are synthesized via the wet chemical reduction method. • 2. The surface of Cu 2 O catalysts is reconstructed in situ to form Cu 2 O/Cu catalysts with highly active interface during converting CO 2 to C 2+ products. • 3. Cu 2 O/Cu catalyst shows the maximum FE C2+ values of 70.0% for CO 2 RR at -1.2 V vs. RHE in 0.1 M KCl. • 4. The Cu 2 O/Cu interface enhances the *CO adsorption and decrease the activation energy of C-C coupling. Converting CO 2 to value-added chemicals and fuels by the electrocatalytic reduction reaction (CO 2 RR) is a promising strategy for reducing CO 2 emissions and achieving clean energy storage. Herein, Cu 2 O catalysts with various morphologies (hexapod concave rhombic dodecahedrons microcrystals enclosed with (331), (111) and (100) facets (D-Cu 2 O), cubic microcrystals enclosed with (100) facet (C-Cu 2 O) and octahedron microcrystals with (111) and (100) facets (O-Cu 2 O)) are prepared via the wet chemical reduction method. The in-situ formation of D-Cu 2 O/Cu, C-Cu 2 O/Cu and O-Cu 2 O/Cu surface/interface and the conversion mechanism of CO 2 to C 2+ products have been systematically studied. The electrocatalytic performance of D-Cu 2 O/Cu for CO 2 to form C 2+ products is superior to that of C-Cu 2 O/Cu and O-Cu 2 O/Cu, which the Faraday efficiencies (FE) of C 2+ products (ethylene and ethanol) reaches 70%. The experimental results combined in-situ Raman spectroscopy and density function theory (DFT) calculations demonstrate that the good electrochemical performance is relate to the surface reconstruction and facet interface, which provides a positive local electronic environment to enhance the adsorption of *CO intermediates and reduces the energy barrier for the activation the C-C coupling. This study will provide a new approach to improve the selectivity of CO 2 RR by interface engineering and surface.