Ni2P/Fe2P encapsulated in N, P co-doped carbon shell as overall water splitting catalyst for wide pH range electrochemical applications

Abstract

It is necessary to fabricate an oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalyst that can be used in the electrolyte (alkaline, acidic) using earth abundant resources. Herein, we fabricated Ni2P/ Fe2P@NPC catalyst using hydrothermal synthesis and phosphide process. Phosphorus can be combined with a transition metal to improve catalytic performance and electrical conductivity. In addition, forming a carbon shell on the surface of the transition metal and doping the carbon shell with phosphorus can contribute to the improvement of electrochemical catalyst stability. N and P are co-doped in the carbon shell to provide more active sites. Therefore, improved catalytic performance can be expected for Ni2P/Fe2P @NPC. Overpotential of the synthesized Ni2P/Fe2P@NPC for OER in alkaline, HER in alkaline, and HER in acidic were confirmed to be 237.8 mV, 208.2 mV and 155.3 mV (at 10 mA cm(-2) in 1 M KOH, 0.5 M H2SO4), respectively. In addition, enhanced stability results were confirmed with 24 hr and 3000 cycle tests.