Highly efficient oxygen evolution and stable water splitting by coupling NiFe LDH with metal phosphides

It is a great challenge to develop highly active oxygen evolution reaction (OER) electrocatalysts with superior durability. In this study, a NiFe layered double hydroxide-decorated phosphide (NiFe LDH@CoP/NiP3) was constructed to display satisfactory OER activity and good stability for water splitting in alkaline media. At an overpotential of 300 mV, NiFe LDH@CoP/NiP3 achieved a current density of 82 mA cm−2 for the OER, which was 9.1 and 2.3 times that of CoP/NiP3 and NiFe LDH, respectively. Moreover, the reconstruction behavior, during which oxyhydroxides formed, was studied by a combination of X-ray photoelectron spectroscopy, Raman spectroscopy, and scanning electron microscopy. A synergistic effect between NiFe LDH and CoP/NiP3 was also observed for the hydrogen evolution reaction. Furthermore, when NiFe LDH@CoP/NiP3 acted as both the cathode and anode for overall water splitting, a high current density of 100 mA cm−2 was maintained for more than 275 h. In addition, under Xe light irradiation, a solar to hydrogen efficiency of 9.89% was achieved for solar-driven water splitting. This work presents the coupling of different active compositions, and can provide a reference for designing bi-functional electrocatalysts.