The sluggish charge transfer and poor intrinsic activity are the bottlenecks that hamper the further development of electrocatalysts for hydrogen evolution. A novel core–shell heterostructure of Cu₃P@Ni is fabricated, which is composed of Cu₃P nanorods covered by metallic Ni. The as-prepared Cu₃P@Ni exhibits a durable and superior activity toward hydrogen evolution, with an overpotential of 42 mV to deliver 10 mA·cm⁻² and a Tafel slope of 41 mV·dec⁻¹. Charge redistribution is observed after successfully constructing the core–shell heterostructure, leading to the altered electronic structure. The theoretical calculations have manifested that Cu₃P@Ni exhibits a zero bandgap and optimized adsorption strength of intermediates, which could give rise to the accelerated charge transfer as well as increased intrinsic activity. This work could shed light on the development of novel electrocatalysts with modulated electronic structure for highly efficient hydrogen evolution.

Transition metal phosphides (TMPs) are promising candidates for noble metal free electrocatalysts in water splitting applications. In this work, we present the facile synthesis of nickel cobalt phosphide electrocatalyst with three-dimensional nanostructure (3D-NiCoP) on the nickel foam, via hydrothermal reaction and phosphorization. The as-prepared electrocatalyst exhibits an excellent activity for hydrogen evolution reaction (HER) in both acidic and alkaline electrolytes, with small overpotentials to drive 10 mA/cm² (80 mV for 0.5 M H₂SO₄, 105 mV for 1 M KOH), small Tafel slopes (37 mV/dec for 0.5 M H₂SO₄, 79 mV/dec for 1 M KOH), and satisfying durability in long-term electrolysis. 3D-NiCoP also shows a superior HER activity compared to single metal phosphide, such as cobalt phosphide and nickel phosphide. The outstanding performance for HER suggests the great potential of 3D-NiCoP as a highly efficient electrocatalyst for water splitting technology.