Carbon Dioxide Valorization via Formate Electrosynthesis in a Wide Potential Window

Abstract The electrochemical CO 2 reduction reaction (CO 2 RR) is a promising strategy to convert CO 2 to carbon‐based fuels and to simultaneously reduce the emission of greenhouse gases into the atmosphere. In this work, the bismuth subcarbonate nanoflowers (BOC NFs) are facilely prepared through a one‐pot synthesis method for efficient formate electrosynthesis through CO 2 RR. Benefiting from the crystal structure and sheet‐stacked morphology, the in situ measurements and theoretical calculation results reveal the self‐reinforced CO 2 adsorption properties and rapid CO 2 adsorption–desorption kinetics on the catalyst surface, which significantly facilitate the CO 2 RR process. As a result, the desirable Faradaic efficiencies of over 90%, with a maximum value of 98.9%, toward formate formation, are achieved in a wide potential window from −0.8 to −1.4 V in an H‐type cell. Moreover, in a flow cell, the superior intrinsic activity of BOC NFs guarantees the high throughput electrocatalytic performance of CO 2 RR and the FE formate of over 90% with high current density is achieved in a potential range as wide as 1200 mV, demonstrating the great potential of BOC NFs for practical CO 2 RR applications. These results underscore the effectiveness of designing electrocatalysts with self‐reinforced CO 2 adsorption properties to improve electrocatalytic performance for efficient CO 2 RR.