Ti₃C₂T_<i>x</i> MXene embedded with nickel-molybdenum sulfide for a high-performance hydrogen evolution reaction in alkaline media

Transition-metal chalcogenides have emerged as strong candidates for the hydrogen evolution reaction (HER) due to their exceptional catalytic activity. A facile synthetic method of Ti₃C₂T _<i>x</i> MXene, and transition-metal chalcogenides (specifically nickel-molybdenum sulfide), and their hybrid formation <i>via in situ</i> growth of nickel-molybdenum sulfide within MXene 2D nanosheets (NiMo₃S₄-MXene) is reported. The synthesis of these electrocatalysts was confirmed through X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Electrochemical studies of NiMo₃S₄ and NiMo₃S₄-MXene were conducted after depositing these materials onto nickel foam, which served as the "current collector". The HER performance of NiMo₃S₄ was significantly enhanced in an alkaline medium after forming a hybrid with MXene (NiMo₃S₄-MXene). The overpotential was found to be 104 mV at 10 mA cm^-2, and the Tafel slope for the HER was 52 mV dec^-1. NiMo₃S₄-MXene exhibited remarkable durability and a low charge-transfer resistance (<i>R</i> _ct = 2.18 Ω). The high electrical conductivity of MXene ensured efficient electron transport to active sites, whereas NiMo₃S₄ offered excellent catalytic activity, facilitating proton adsorption and hydrogen generation. Thus, a synergistic effect arises from the complementary properties of the components in the hybrid electrocatalyst, resulting in favourable characteristics for the HER. These findings suggest that the transition-metal chalcogenides, in combination with MXene, could serve as efficient and durable electrocatalysts for electrochemical water-splitting.