Atypical Oxygen-Bearing Copper Boosts Ethylene Selectivity toward Electrocatalytic CO Reduction.

Oxygen-bearing copper (OBC) has been widely studied for enabling the C-C coupling of the electrocatalytic CO reduction reaction (CORR) since this is a distinctive hallmark of strongly correlated OBC systems and may benefit many other Cu-based catalytic processes. Unresolved problems, however, include the instability of and limited knowledge regarding OBC under realistic operating conditions, raising doubts about its role in CORR. Here, an atypical and stable OBC catalyst with a hierarchical pore and nanograin-boundary structure was constructed and was found to exhibit efficient CORR for the production of ethylene with a Faradaic efficiency of 45% at a partial current density of 44.7 mA cm in neutral media, and the ethylene partial current density is nearly 26 and 116 times that of oxygen-free copper (OFC) and commercial Cu foam, respectively. More importantly, the structure-activity relationship in CORR was explored through a comprehensive analysis of experimental data and computational techniques, thus increasing the fundamental understanding of CORR. A systematic characterization analysis suggests that atypical OBC (CuO) was formed and that it is stable even at -1.00 V [(vs the reversible hydrogen electrode (RHE)]. Density functional theory calculations show that the atypical OBC enables control over CO adsorption and dimerization, making it possible to implement a preference for the electrosynthesis of ethylene (C) products. These results provide insight into the synthesis and structural characteristics of OBC as well as its interplay with ethylene selectivity.