Large numbers of catalysts have been developed for the electrochemical reduction of CO 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 (Bi O -NGQDs) for highly efficient electrochemical reduction of CO to formate. Bi O -NGQDs demonstrates a nearly 100 % formate Faraday efficiency (FE) at a moderate overpotential of 0.7 V with a good stability. Strikingly, Bi O -NGQDs exhibit a high activity (average formate FE of 95.6 %) from -0.9 V to -1.2 V 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 CO (ads) and OCHO* intermediate after combination with NGQDs.

Although Faraday efficiency (FE) for CO production of single-atom catalysts immobilized on nitrogen-doped carbon supports (M-N/C) for CO2 electrocatalytic reduction reaction (CO2RR) is generally over 90%, M-N/C catalysts demonstrate a...