Superhydrophilic self-supported Y-doping Ni2P electrode for robust alkaline hydrogen evolution at large current density

The development of efficient and stable alkaline hydrogen evolution catalyst under high current density is essential for the large-scale application of alkaline water electrolysis technology. Here, we prepare a superhydrophilic self-supported Y-doping Ni2P electrode (Y-Ni2P@GP) by an electrodeposition method following high-temperature phosphorization, which exhibits an excellent alkaline hydrogen evolution reaction (HER) activity at high current density. At 500 mA cm−2, the Y-Ni2P@GP electrode requires a much lower overpotential (160 mV) than the Pt/C(20 %)@GP and pure Ni2P@GP electrodes, and stably operates for 300 h with negligible degradation. The enhanced catalytic performance of the Y-Ni2P@GP electrode is attributed to that the doped oxyphilic Y atom as robust water-dissociation site prominently accelerates the sluggish Volmer step of alkaline HER, which collaborates with highly efficient Ni hydrogen adsorption sites to boost the overall HER kinetics. Furthermore, its superhydrophilic electrode surface facilitates H2 bubble detachment with small and uniform sizes, and its self-supported electrode structure with strong catalyst adhesion ensures the rapid transfer of electrons and prevents the fall off of catalyst. This further improves the catalytic efficiency and stability under high current density.