▎ 摘　　要

Achieving high electrochemical conversion of carbon dioxide (CO2) into valuable fuels and chemicals is one of the most promising directions to address environmental and energy challenges. Although several single-crystal based studies and simulation results have reported that rich in steps on Cu (100) surfaces are favorable to convert toward C-2 alcohol products, most studies are still stuck in low-index (100) facets or surface defect-derived low density of step-sites. In the present work, we report the high production of ethanol by synthesizing a wrinkled Cu catalyst with high facets via a chemical vapor deposition (CVD) graphene growth process. Under our approach, we used graphene as a guiding material to produce wrinkled Cu film for use as an electrocatalyst. The graphene-grown Cu films are not only mass-producible but composed of a high density of step-sites with high-facet atomic arrangements, including the (200) and (310) facets, which are difficult to synthesize using existing methods. The wrinkled Cu film with a unique atomic arrangement showed high ethanol selectivity, achieving 40% faradaic efficiency (FE) at -0.9 V vs reversible hydrogen electrode (RHE), one of the largest selectivity values reported thus far for a Cu-based CO2 conversion catalyst. The C-2 selectivity and productivity was 57% FE and -2.2 mA/cm(2) at -1.1 V vs RHE, respectively. Density functional theory (DFT) calculation results demonstrated that such a high ethanol productivity is mainly attributable to the (310) facet of the wrinkles, which feature a low C-C coupling barrier (0.5 eV) and a preferred reaction path toward ethanol among other products.