Enhancing the activity of transition metal-based sulfides via synergistic effects for electrochemical overall water splitting

Transition metal sulfides have emerged as promising catalysts for electrochemical water splitting, a critical process for hydrogen generation. However, single transition metal sulfides often suffer from low catalytic performance, limiting their practical applications. In contrast, composite transition metal sulfides have demonstrated superior catalytic properties due to synergistic effects between multiple metals. In this work, a tri-transition metal sulfide (MoNiFeS) was synthesized using a solvothermal method to explore its potential for improving water splitting efficiency. The synthesized MoNiFeS catalyst exhibited excellent electrochemical activity for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The overpotentials required for OER were 190 mV and 305 mV, and for HER were 247 mV and 385 mV at current densities of 40 mA cm⁻² and 100 mA cm⁻², respectively. Furthermore, in a conventional two-electrode electrolyzer setup, a voltage of 1.48 V was required to achieve a current density of 10 mA cm⁻², highlighting the potential of MoNiFeS as a high-performance catalyst for overall water splitting. These findings suggest that tri-transition metal sulfides, such as MoNiFeS, offer a promising avenue for enhancing the efficiency of electrochemical water splitting and hydrogen production.