Tuning hydrogen binding energy by interfacial charge transfer enables pH-universal hydrogen evolution catalysis of metal phosphides

Transition metal phosphides (TMPs) are new-generation electrocatalysts for Hydrogen evolution reaction (HER), but the performance is still far less than that of noble-metal catalysts due to the strong interactions between the adsorbed H and the intensely electronegative P. Herein, we propose a controllable phosphorization strategy to construct phosphorus-rich and metal-rich (Fe, Ni)3P/NiCoP heterojunction arrays to tune the hydrogen binding energy. The homologous elements distribution and well defined configuration ensure the low Schottky barriers and effective exposure of the catalytic active sites. Theoretical calculations prove that the interfacial charge transfer can modulate the charge density around the active sites for mediating the hydrogen adsorption energy. As expected, the constructed (Fe,Ni)3P/NiCoP catalysts exhibit extraordinary pH-universal Pt-like activity and high stability, with overpotentials of 50.9, 70.5 and 52.3 mV at a current density of 10 mA cm−2 in acidic, neutral and alkaline electrolytes, respectively. Our finding builds a legible connection between atomic/interface/electronic structure and intrinsic properties for designing high-efficiency catalytic materials.