An efficient NiO/NiS/NiP heterostructure catalyst for oxygen evolution reaction

Hydrogen production through water splitting is crucial and hydrogen is considered a potential fuel for the future. To make water splitting commercially viable, inexpensive transition metal-based catalysts owing better efficiency and higher stability are needed. We have synthesized NiO, NiS, NiP, and their binary (NiO/NiS and NiS/NiP) and ternary (NiO/NiS/NiP) heterostructures catalysts. Synthesized catalysts have been analyzed through scanning electron microscopy, Fourier-transformed infrared, and X-ray diffraction spectroscopies for their structural characterization. The catalytic performance of all the synthesized catalysts has been evaluated towards oxygen evolution reaction (OER). The NiO/NiS/NiP heterostructure has been shortlisted as an efficient and stable electrocatalyst. The onset potential for OER has been found to be 1.49 V (vs. RHE) along with an overpotential of 262 mV @ 40 mA/cm2 current density and 60 mV dec-1, Tafel slope manifest the heterostructure as the best contender for OER compared to its counterparts (NiO, NiS and NiP) under similar water oxidation conditions. These results prove reported heterostructure is an efficient catalyst than nickel-based benchmark electrocatalysts. Moreover, controlled potential electrolysis has been performed for all electrocatalysts by chronoamperometry at 1.65 V (vs. RHE) and current density has been measured for an extended period of > 12 h which showed that most of the catalysts are stable enough.