Self-supported tungsten-doped nickel-iron layered phosphides for efficient electrocatalytic alkaline water splitting

Although layered double hydroxides (NiFe-LDH) have demonstrated adequate oxygen evolution reaction (OER) performance since their inception, their low hydrogen evolution performance has traditionally limited their application in overall water splitting (OWS). In this study, FeWO4@Ni2P/FeNiP (NiFeW-P) self-supported nanosheets were grown on NF (NiFeW-P@NF) using cation doping and subsequent anion exchange processes. NiFeW-P@NF with lower crystallinity exhibited more corners and edges, thereby exposing numerous catalytic active sites and greatly improving both oxygen and hydrogen evolution performance. Excellent electrocatalytic hydrogen evolution reaction (HER) and OER activity were demonstrated by the produced NiFeW-P@NF catalysts, achieving reaction current densities of 10 mA.cm(-2) with overpotentials of just 81 mV and 174 mV, respectively. Moreover, they exhibited stability for over 100 hours at current densities around 1000 mA.cm(-2). When assembled into an alkaline electrolyzer, NiFeW-P@NF sustained an OWS current density of approximately 1200 mA.cm(-2) for more than 100 h at just 1.48 V. This work sheds more light on the evolution of NiFe-LDH's enhanced electrocatalytic OWS characteristics.