Three-Dimensional Porous MnCo2S4 Microrugby Balls Supported on Carbon Cloth for Efficient Oxygen Evolution Reaction

The design and development of oxygen evolution electrocatalyst with stable structure and outstanding performance is of great significance for hydrogen production by water electrolysis. Inspired by the high stability of the self-supported catalyst and the synergistic effect of the bimetallic transition metal catalyst, MnCo2S4 microrugby balls were successfully prepared on carbon cloth by a two-step hydrothermal method in this work. The prepared MnCo2S4/CC exhibits remarkable electrochemical performance due to the stable self-supporting design and lavish porous structure, as well as the high inherent electrical conductivity of sulphide. The overpotential of MnCo2S4/CC is only 180 mV at the current density of 10 mA cm(-2), which is 161 mV lower than that of MnCo2O4/CC (341 mV). The Tafel slope of MnCo2S4/CC is 145.7 mV dec(-1), which is less than that of MnCo2O4/CC (157.5 mV dec(-1)). The OER performance of MnCo2S4/CC is significantly improved due to its high electrochemically active surface area and conductivity. Density functional theory (DFT) calculations show that MnCo2S4/CC has a higher electron density than MnCo2O4/CC, which indicates that it has better conductivity. These results indicate that it is a feasible method to optimize the performance of the electrocatalysts by combining the large electrochemical surface area provided by the porous structure of the self-supported catalyst and the large electrical conductivity of the sulphide.