Electroreduction of CO2 to formate with excellent selectivity and stability on nano-dendrite Bi film electrode

Abstract Electroreduction of CO2 into value-added fuels has been considered as a promising technology to mitigate the CO2-invoked greenhouse effect. However, the poorer selectivity and lower stability of electrocatalysts still impede its development. In this work, we prepared a nano-dendrite Bi film electrode by simple one-step electrodeposition method. The Bi (1200) (deposition time of 1200s) exhibited a superior catalytic activity in a wide potential towards CO2-to-formate conversion and acquired the maximum faradaic efficiency (FEformate) of 97.5 % at –1.5 V vs Ag/AgCl. More encouragingly, it showed an excellent stability as the FEformate maintained ∼ 90 % over 108 h of electrolysis which outperformed most of the reported Bi-based electrodes. The notable performance was mainly attributed to the thorn-like structure which afforded massive active sites. Meantime, Bi-O structure on oxide-derived Bi was beneficial for CO2 adsorption and activation with accelerated interfacial charge transfer process. Moreover, the well-preserved electrode morphology and Bi-O component enabled its longer stable service life. This result implied Bi film electrode would be a promising candidate for efficient CO2 electroreduction.