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

Abstract

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 Cu1.81S particles supported on multi-walled carbon nanotube (MWCNT) composites (Cu1.81S@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 -0.47 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, Cu1.81S@WMCNT-600-OD exhibits a high CO2 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 CO2 reduction. Therefore, this work provides low-cost, abundant, and efficient catalysts for CO2ER and a facile pathway that improves the electrocatalytic performance.