Hydrothermal synthesis of MoSe₂/Ni₃Se₄ heterostructures anchored on high-entropy M₄C₃T_x (M = Ti, V, Mo, Nb, Ta) with superior hydrogen evolution reaction activity

Developing hydrogen evolution reaction (HER) electrocatalysts with high activity in both acidic and alkaline media is of great significance for adapting to diverse electrolytic environments. In this study, MoSe₂ and Ni₃Se₄ nanosheets were successfully composited on high-entropy M₄C₃T_x MXene (M = Ti, V, Mo, Nb, Ta) via a hydrothermal method, constructing a novel heterostructured catalyst. This design leverages the excellent conductivity and multielement synergistic effect of high-entropy MXenes, which not only facilitates electron transport but also provides a robust platform for the uniform distribution of MoSe₂ and Ni₃Se₄ nanosheets, thereby exposing abundant active sites. Electrochemical tests indicate that the catalyst exhibits excellent HER performance in both 0.5 M H₂SO₄ and 1.0 M KOH electrolytes. Specifically, under acidic conditions, MoSe₂/Ni₃Se₄/M₄C₃T_x shows an overpotential of only 67 mV at a current density of 10 mA·cm⁻² with a Tafel slope of 68.7 mV·dec⁻¹, while under alkaline conditions, the overpotential at 10 mA·cm⁻² is 73 mV with a Tafel slope of 77.8 mV·dec⁻¹. Moreover, the catalyst demonstrates excellent long-term stability in both acidic and alkaline media. This work provides a new strategy for designing efficient and stable HER catalysts suitable for harsh acid–base environments.