Interface Engineering of Ni₃S₂ and Zeolitic Imidazolate Framework-67: Enhancing the Overall Electrochemical Water Splitting

Recent progress on a metal-free and highly efficient electrocatalyst for the production of oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) during the water electrolysis process makes it highly suitable to produce clean and sustainable renewable hydrogen energy. The electrocatalyst of Ni₃S₂/ZIF-67 composite prepared by a facile precipitation method and which exhibits excellent catalytic activity for overall OER and HER performances with a small Tafel slope (92.1 and 61.8 mV/dec), low overpotential (130 and 76 mV at 10 mA cm^-2 current density), and high and long durability for 24 h at constant 10 mA cm^-2 current density in 1 M KOH electrolyte. As-prepared Ni₃S₂/ZIF-67 composite, working as both anode and cathode in two-electrode configurations for overall electrochemical water splitting performance, was analyzed in an alkaline (1 M KOH) solution, and it exhibits superior oxidation performance with a low cell voltage of 1.47 V and good stability for 12 h. The interface engineering between ZIF-67 and Ni₃S₂ facilitates charge transfer, exposes abundant active sites, and enhances the HER and OER performance. The results of the composite displayed an exceptional electrocatalyst for economical applications compared with the bare Ni₃S₂ and ZIF-67.