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

The CO₂ electroreduction reaction (CO₂ER) 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 CO₂. Herein, we develop an oxide-modification of Cu_1.81S particles supported on multi-walled carbon nanotube (MWCNT) composites (Cu_1.81S@WMCNT-600-OD) through a facile in-situ crystallization strategy. This modification improves the electroreduction activity in the reduction CO₂ to formate with a low onset-potential of-0.47âV vs RHE (overpotentialâ=â0.25âV). In addition, the material used in preparing this catalyst is widely accessible at low cost. Among the electrocatalysts tested, Cu_1.81S@WMCNT-600-OD exhibits a high CO₂ selectivity towards formate at an overpotential of 0.45âV with high faradaic efficiency (82 %) for nearly 20âh. Further investigations reveal that the needle-like dendritic structure formed during electrolysis is the likely source for the improved performance in CO₂ reduction. Therefore, this work provides low-cost, abundant, and efficient catalysts for CO₂ER and a facile pathway that improves the electrocatalytic performance.