Highly Efficient Hydrogen Evolution by Self-Standing Nickel Phosphide-Based Hybrid Nanosheet Arrays Electrocatalyst*

Hydrogen evolution electrocatalyst made from earth-abundant elements for electrocatalytic water splitting is essential for sustainable and clean hydrogen economy. At present, how to make efficient catalysts with superior catalytic activity from cheap raw materials in large scale remains a great challenge. Here, we report a new nickel phosphide-based hybrid nanosheet arrays electrocatalyst, synthesized by a one-step phosphorization of commercial nickel (Ni) foam, for hydrogen evolution in water splitting. In acidic medium, the nickel phosphide nanosheet arrays exhibit very stable and fast hydrogen evolution kinetics with a relatively low overpotential of -61 mV and -121 mV to achieve current densities of -10 and -100 mA cm^-2, respectively, with a Tafel slope of 51 mV dec^-1, showing comparable performance to the most efficient non-noble metal based hydrogen evolution electrocatalysts reported so far. This robust electrocatalyst, made from commercially available materials, holds a potential for the industrialization of clean hydrogen energy.