Ternary metal phosphide nanosheets as a highly efficient electrocatalyst for water reduction to hydrogen over a wide pH range from 0 to 14

Developing highly active electrocatalysts for the hydrogen evolution reaction (HER) is crucial to construct an efficient water-splitting device. In this present study, a novel ternary cobalt-nickel phosphide nanosheet with nanowire edges on 3D nickel foam (CoNiP@NF) was first synthesized and used as an excellent cathode for the HER over a wide pH range from 0 to 14. The cathode showed high-performance catalytic activity to produce hydrogen in aqueous solution, with quite low overpotentials of only 60 mV (0.5 M H2SO4, pH similar to 0.26), 120 mV (1.0 M KPi, pH similar to 7), and 155 mV (1.0 M KOH, pH similar to 14) to reach a current density of 10 mA cm(-2). This high performance is probably due to the combination of the advantages of both one-dimensional nanowire and two-dimensional nanosheet materials, which can effectively improve the electrochemical performance for the HER. To the best of our knowledge, the present ternary CoNiP material is among the best noble-metal-free electrocatalysts for hydrogen evolution in water.