Boosting *CO coverage on Cu octahedra enclosed by Cu(1 1 1) for efficient CO2 electroreduction to C2H5OH

Copper (Cu) electrocatalysts for carbon dioxide reduction reaction (CO2RR) have attracted much attention due to their ability to produce high value-added C2+ products (e.g., C2H4, C2H5OH, and n-propanol). However, achieving high selectivity of Cu electrocatalysts for C2H5OH in aqueous-based electrolytes remains a significant challenge. In this paper, we report Cu octahedra modified with low-coordinated Cu nanoclusters (Cu oct @Cu_NCs) as an efficient electrocatalyst for CO2RR to C2H5OH. Notably, the defect-site-rich Cu nanoclusters can promote the adsorption of *CO and increase the *CO coverage on Cu octahedra enclosed by Cu(1 1 1), thus promoting CO2RR to C2H5OH. We achieved a high Faradaic efficiency(FE) of 48.16 % for C2H5OH, and that of the C2+ products is 83.31 % at −1.17 V vs. RHE. This study provides a surface nanostructured route for rationalizing efficient and selective copper electrocatalysts for CO2RR.