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 (CO 2 RR) have attracted much attention due to their ability to produce high value-added C 2+ products (e.g., C 2 H 4 , C 2 H 5 OH, and n-propanol). However, achieving high selectivity of Cu electrocatalysts for C 2 H 5 OH 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 CO 2 RR to C 2 H 5 OH. 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 CO 2 RR to C 2 H 5 OH. We achieved a high Faradaic efficiency (FE) of 48.16 % for C 2 H 5 OH, and that of the C 2+ 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 CO 2 RR.