Facile synthesis of self-supported intertwined columnar NiCoP as a high efficient electrocatalyst for hydrogen evolution reaction

Abstract

A new self-supported nickel-cobalt phosphide (NiCoP) on Ni foam (NiCoP/NF) is fabricated by simple immersion in Co(NO3)2 solution followed by subsequent phosphorization. NiCoP/NF displays intertwined and porous columnar morphology derived from topological transformation of corresponding columnar amorphous hydroxides precursor. NiCoP/NF manifests the most prominent hydrogen evolution reaction (HER) performance in both 0.5 M H2SO4 and 1 M KOH with the overpotentials of 49 and 57 mV to achieve 10 mA cm−2, respectively. Also, NiCoP/NF showed excellent oxygen evolution reaction (OER) performance, requiring 256 mV to achieve 10 mA cm−2, even superior to that of RuO2 and IrO2. Such impressive HER performance of NiCoP/NF is mainly attributed to the collective effects of enlarged surface area and enriched exposed active sites, affording faster charge transfer kinetic in HER process. This simple immersion method offers a new insight to design cost-effective and efficient electrocatalysts for large scale application.