The site pair matching of a tandem Au/CuO–CuO nanocatalyst for promoting the selective electrolysis of CO(2) to C(2) products

Tandem catalysis, in which a CO(2)-to-C(2) process is divided into a CO(2)-to-CO/*CO step and a CO/*CO-to-C(2) step, is promising for enhancing the C(2) product selectivity when using Cu-based electrochemical CO(2) reduction catalysts. In this work, a nanoporous hollow Au/CuO–CuO tandem catalyst was used for catalyzing the eCO(2)RR, which exhibited a C(2) product FE of 52.8% at −1.0 V vs. RHE and a C(2) product partial current density of 78.77 mA cm(−2) at −1.5 V vs. RHE. In addition, the C(2) product FE stably remained at over 40% over a wide potential range, from −1.0 V to −1.5 V. This superior performance was attributed to good matching in terms of the optimal working potential and charge-transfer resistance between CO/*CO-production sites (Au/CuO) and CO/*CO-reduction sites (CuO). This site pair matching effect ensured sufficient supplies of CO/*CO and electrons at CuO sites at the working potentials, thus dramatically enhancing the formation rate of C(2) products.