Electroreduction of CO₂to formate with excellent selectivity and stability on nano-dendrite Bi film electrode

Electroreduction of CO₂into 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 (FE_formate) of 97.5 % at -1.5 V vs Ag/AgCl. More encouragingly, it showed an excellent stability as the FE_formatemaintained ∼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 CO₂adsorption 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 CO₂electroreduction.