Bi-Eu bimetallic catalysts enabling ultrastable electroreduction of CO2 with a ∼ 100% formate Faradaic efficiency

Electrochemical reduction of CO2 (ERCO2) is an effective way to convert CO2 into useful chemical products. However, most catalysts used for ERCO2 show poor selectivity and stability. Here, we design a Bi8Eu1 bimetallic catalyst, which exhibits both excellent stability (>400 h) and Faradaic efficiency for formate production (∼100% at − 0.89 VRHE). Moreover, high Faradaic efficiency (>97%) is observed over a wide potential window (from − 0.89 VRHE to − 1.19 VRHE). In a flow-cell, the Bi8Eu1 catalyst shows an ultra-high current density of 250 mA cm−2 at − 0.77 VRHE. Density functional theory calculations indicate that the Bi-Eu interactions activate the Bi sites for strongly stabilizing *OCHO intermediates, thus promoting the conversion of CO2 to formate. This work provides insights into the design of excellent electrocatalysts for ERCO2 with improved activity and durability.