Increased water splitting activity of self-supported 3D nanoporous Ni and Co-based phosphides prepared by dealloying and electrophoretic deposition

The production of hydrogen by water electrolysis is an essential route to promote hydrogen energy. Design catalysts with plenty of active sites and non-precious metals is the key to realizing hydrogen production by water cracking. We have prepared nanoporous NiCoP using a dealloying method, and deposited the resultant NiCoP on sulfide-treated nickel foam (NF) by electrophoretic deposition to give a nanoporous NiCoP/Ni3S2/NF composite water electrolysis catalyst. The NiCoP-Ni3S2 heterostructure exhibits an abundance of active sites, and the self-supporting structure enhances electron transfer rate, resulting in superior hydrogen evolution reaction (HER) activity and good oxygen evolution reaction (OER) activity using the NiCoP/Ni3S2/NF composite electrode. The associated HER over- potential in a KOH electrolyte was 27 mV with a Tafel slope of 83 mV/dec and a current density of 10 mA/cm2. The OER over-potential was 353 mV at the current density was 100 mA/cm2. The results generated serve to establish a general method for the preparation of high-performance and low-cost self-supported catalysts for water splitting.