Correlating the valence state of a Cu-based electrocatalyst for CO 2 reduction to C 2 .

In this study, a facile ligand-protected strategy for preparing Cu@Cu 2 O and CuO nanoparticles is presented. The electrocatalyst efficacy of the CuO variant, particularly for CO 2 reduction to multi-carbon products (C 2+ ), is significant, boasting faradaic efficiencies (FEs) surpassing 85% and a current density peak at 340 mA cm -2 . This exceptional performance markedly exceeds that of the Cu@Cu 2 O electrocatalyst. This observed enhancement in the electrosynthesis efficiency of C 2+ is attributed to the abundant Cu 0 active sites, which originate from the in situ electroreduction of CuO.