Oxidation-induced restructuring of copper sulfides for enhanced performance in CO2 electroreduction

The CO 2 electroreduction reaction (CO 2 ER) is a reliable pathway that enables a balanced carbon cycle for sustainable development strategies. There are several major challenges, such as selectivity , efficiency, and stability of the electrocatalysts that need to be addressed for the widespread application of this in the reduction of CO 2 . Herein, we develop an oxide-modification of Cu 1.81 S particles supported on multi-walled carbon nanotube (MWCNT) composites (Cu 1.81 S@WMCNT-600-OD) through a facile in-situ crystallization strategy. This modification improves the electroreduction activity in the reduction CO 2 to formate with a low onset-potential of -0.47 V vs RHE (overpotential = 0.25 V). In addition, the material used in preparing this catalyst is widely accessible at low cost. Among the electrocatalysts tested, Cu 1.81 S@WMCNT-600-OD exhibits a high CO 2 selectivity towards formate at an overpotential of 0.45 V with high faradaic efficiency (82 %) for nearly 20 h. Further investigations reveal that the needle-like dendritic structure formed during electrolysis is the likely source for the improved performance in CO 2 reduction. Therefore, this work provides low-cost, abundant, and efficient catalysts for CO 2 ER and a facile pathway that improves the electrocatalytic performance.