Fabrication of Core-Sheath NiCoP@FePx Nanoarrays for Efficient Electrocatalytic Hydrogen Evolution

Construction of effective, stable, eco-friendly, and earth-abundant electrocatalysts that substitute noble metals for hydrogen evolution reaction (HER) is essential for developing renewable and clean energy. Here we report a layer-by-layer assembly route to fabricate core-sheath structured nanoarrays composed of nickel cobalt phosphide and iron phosphide (NCP@FePx) on a conductive Ni wire by atomic layer deposition (ALD). The as-fabricated multimetallic phosphide exhibits high electro-catalytic activity in both alkaline and acidic media, with small overpotentials of 82.5 and 96 mV at 10 mA cm(-2), respectively. The self-supported electrode displays superior long-term stability and favorable durability. The excellent activity is originated from the unique core-sheath structure, and the synergistic effects of the FePx sheath and the NCP core contributed to the enhanced activity. The present ALD-assisted layer-by-layer strategy may provide a general route for the controlled fabrication of nanostructured electrocatalysts with tunable compositions and surfaces.