Integrated “Two‐in‐One” Strategy for High‐Rate Electrocatalytic CO 2 Reduction to Formate

Abstract The electrochemical CO 2 reduction reaction (ECR) is a promising pathway to producing valuable chemicals and fuels. Despite extensive studies reported, improving CO 2 adsorption for local CO 2 enrichment or water dissociation to generate sufficient H* is still not enough to achieve industrial‐relevant current densities. Herein, we report a “two‐in‐one” catalyst, defective Bi nanosheets modified by CrO x (Bi−CrO x ), to simultaneously promote CO 2 adsorption and water dissociation, thereby enhancing the activity and selectivity of ECR to formate. The Bi−CrO x exhibits an excellent Faradaic efficiency (≈100 %) in a wide potential range from −0.4 to −0.9 V. In addition, it achieves a remarkable formate partial current density of 687 mA cm −2 at a moderate potential of −0.9 V without iR compensation, the highest value at −0.9 V reported so far. Control experiments and theoretical simulations revealed that the defective Bi facilitates CO 2 adsorption/activation while the CrO x accounts for enhancing the protonation process via accelerating H 2 O dissociation. This work presents a pathway to boosting formate production through tuning CO 2 and H 2 O species at the same time.