The site pair matching of a tandem Au/CuO-CuO nanocatalyst for promoting the selective electrolysis of CO to C products.

Tandem catalysis, in which a CO-to-C process is divided into a CO-to-CO/*CO step and a CO/*CO-to-C step, is promising for enhancing the C product selectivity when using Cu-based electrochemical CO reduction catalysts. In this work, a nanoporous hollow Au/CuO-CuO tandem catalyst was used for catalyzing the eCORR, which exhibited a C product FE of 52.8% at -1.0 V RHE and a C product partial current density of 78.77 mA cm at -1.5 V RHE. In addition, the C 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 products.