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Oxide-derived Cu (OD-Cu) exhibits unique and excellent C 2 product selectivity (ethanol, ethylene, etc.) in the field of electrocatalytic reduction reaction of CO 2 (eCO 2 RR), which has a great application value in realizing effective storage of renewable energy and the artificial closed carbon cycle. However, the Cu 2 O structure encounters complex structure evolution under negative potential conditions, making it difficult to obtain the specific active structures. Here, we found an operando activation strategy for the OD-Cu catalyst based on the cyclic voltammetry (CV) process conducted in CO 2 -saturated solution. Assisted by an interval eCO 2 RR, the sluggish octahedral–Cu 2 O ( o -Cu 2 O) evolves into active Cu/Cu 2 O–CV, with the formed “metallic Cu” uniformly anchoring on o -Cu 2 O and accompanied by rich Cu δ+ –Cu 0 grain boundaries. Combined with in situ and ex situ characterization, compared to o -Cu 2 O, Cu/Cu 2 O–CV significantly promoted the formation of C 2 products (FE C2 increased from 17.13 to 73.44%). By enhancing the adsorption of CO* and subsequently the formation of O*C*COH intermediates, the Faraday efficiency for ethanol was significantly improved from 5.15% (on o -Cu 2 O) to 56.56% (on Cu/Cu 2 O–CV). Our study provides evidence for a previously unexplored function of CO 2 in the evolution of o -Cu 2 O catalysts into highly active structures for the generation of multicarbon products, opening a pathway for the rational design of future catalysts for the electrochemical reduction of CO 2 .
Yang et al. (2022) studied this question.