▎ 摘　　要

Large numbers of catalysts have been developed for the electrochemical reduction of CO2 to value-added liquid fuels. However, it remains a challenge to maintain a high current efficiency in a wide negative potential range for achieving a high production rate of the target products. Herein, we report a 2D/0D composite catalyst composed of bismuth oxide nanosheets and nitrogen-doped graphene quantum dots (Bi2O3-NGQDs) for highly efficient electrochemical reduction of CO2 to formate. Bi2O3-NGQDs demonstrates a nearly 100% formate Faraday efficiency (FE) at a moderate overpotential of 0.7V with a good stability. Strikingly, Bi2O3-NGQDs exhibit a high activity (average formate FE of 95.6%) from -0.9V to -1.2V vs. RHE. Additionally, DFT calculations reveal that the origin of enhanced activity in this wide negative potential range can be attributed to the increased adsorption energy of CO2(ads) and OCHO* intermediate after combination with NGQDs.