A covalency-aided electrochemical mechanism for CO reduction: the synergistic effect of copper and boron dual active sites drives the formation of a high-efficiency ethanol product.

Electrocatalytic carbon dioxide (CO) conversion into high-value multi-carbon products is of great significance for CO utilization, but the chemical inertness, low yields, and poor product selectivity hinder the application prospects of the electrocatalytic conversion methods. In this work, a covalency-aided electrochemical mechanism for CO reduction is proposed for the first time by embedding the nonmetallic element boron (B) on copper surfaces, in which p-block dopants have a significant impact on modifying the adsorbent intermediates and improving the catalytic activity. Herein, B atoms not only provide empty and occupied orbitals to adsorb and activate CO, but also afford a large amount of charge to stabilize the C intermediates. In addition, B atoms can also adjust the oxidation state of nearby copper (namely, Cu), and the synergistic Cu and B dual active sites act as O* adsorption and C* adsorption sites, respectively, leading to strong adsorption and activation of CO. First-principles calculations reveal that CO can be reduced into CHOH with an ultralow potential of -0.26 V. Overall, this study provides new insights into CO reduction, which offers a promising way for achieving an efficient ethanol product.