Organic-Inorganic Metal Phosphonate-Derived Nitrogen-Doped Core-Shell Ni2P Nanoparticles Supported on Ni Foam for Efficient Hydrogen Evolution Reaction at All pH Values

The tunable compositions and heteroatom-enriched characteristics of inorganic-organic metal phosphonate hybrids make them promising templates and precursors to create high-performance nanomaterials as electrocatalysts for hydrogen evolution reaction (HER) by high-temperature pyrolysis or reduction. Herein, nitrogen-doped carbon-coated nickel phosphide nanoparticles in situ supported on Ni foam (termed as Ni2P@NC/NF) were fabricated by hydrogen reduction of nickel phosphonate loaded on Ni foam as precursors. The as-prepared self-supported Ni2P@NC/NF can be directly utilized as an efficient working electrode for HER at all pH values, exhibiting superior activity as compared with Ni-based catalysts and noble metal benchmarks. To drive 10 mA cm(-2), Ni2P@NC/NF demands a low overpotential of 68 mV in 0.5 M H2SO4, 84 mV in 1.0 M KOH, and 155 mV in 1.0 M PBS. This outstanding HER performance of Ni2P@NC/NF might originate from the doping of N atoms, the flexible conductive 3D framework, and the synergistic interaction among the components. Moreover, the unique core-shell structure and stable conductive substrate of Ni2P@NC/NF endow it with long-time stability. This work provides an ideal electrode for electrochemical devices for widespread hydrogen production.