Fast Screening for Copper-Based Bimetallic Electrocatalysts: Efficient Electrocatalytic Reduction of CO 2 to C 2+ Products on Magnesium-Modified Copper.

Electroreduction of CO 2 (CO 2 RR) into high value-added chemicals is an attractive route to achieve carbon neutrality. However, the development of an efficient catalyst for CO 2 RR is still largely by trial-and-error and is very time-consuming. Herein, we built an electrocatalyst testing platform featuring a home-built automatic flow cell to accelerate the discovery of efficient catalysts. A fast screening of 109 Cu-based bimetallic catalysts in only 55 h identifies Mg combined with Cu as the best electrocatalyst for CO 2 to C 2+ products. The thus designed Mg-Cu catalyst achieves a Faradaic efficiency (FE) of C 2+ products up to 80 % with a current density of 1.0 A cm -2 at -0.77 V versus reversible hydrogen electrode (RHE). Systematic experiments with in situ spectroelectrochemistry analyses show that Mg 2+ species stabilize Cu + sites during CO 2 RR and promote the CO 2 activation, thus enhancing the *CO coverage to promote C-C coupling.