Bi 2 S 3 nanofiber bunch for highly efficient CO 2 electroreduction to formate at low overpotential

Electrochemical conversion of CO 2 into valuable chemicals represents a promising strategy to alleviate the environmental issues caused by excessive CO 2 levels in the atmosphere. In this work, Bi 2 S 3 with different morphologies have been fabricated via facile hydrothermal method to investigate the CO 2 electrochemical reduction process. Compared with Bi 2 S 3 nanoflower, Bi 2 S 3 nanofiber bunch displays rather efficient electrochemical conversion of CO 2 to formate with the maximum faradaic efficiency of 96% at − 0.75 V vs. reversible hydrogen electrode (RHE). Experimental results demonstrate that the morphology of nanofiber bunch possesses larger surface area, smaller interfacial charge transfer resistance as well as faster initial electron transfer step during the CO 2 electrocatalytic reaction, which are beneficial for the promotion of CO 2 electrocatalytic properties. By partially replacing S with O atom in Bi 2 S 3 nanoflower and nanofiber bunch, the electrochemical conversion of CO 2 to CO can be promoted. This work offers valuable insights into the design of efficient electrocatalysts towards selective CO 2 conversion.