Hydrothermal synthesis of MoSe ₂ /Ni ₃ Se ₄ heterostructures anchored on high-entropy M ₄ C ₃ T _<i>x</i> (M = Ti, V, Mo, Nb, Ta) with superior hydrogen evolution reaction activity

Developing 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<em>_x</em> MXene (M = Ti, V, Mo, Nb, Ta) via a hydrothermal method, constructing a novel heterostructured catalyst. This design leverages the excellent conductivity and multi-element synergistic effect of high-entropy MXene, which not only facilitates electron transport but 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<em>_x</em> 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.