Hierarchical ZnCoS@CoFe-layered double hydroxide on Ni foam to enhance the OER performance for water splitting

Abstract

For sustainable energy generation technologies, improving the slow kinetics of the electrochemical oxygen evolution reaction (OER) is essential. In this study, a three-step hydrothermal-sulfidation-electrodeposition method was developed to prepare a ZnCoS@CoFe-layered double hydroxide (LDH) heterostructure catalyst on Ni foam (NF). The combination of needle-like and layered structures exhibits good electronic transmission capability. Moreover, the unique construction enhances the gas release rate. In particular, the synergistic effect of ZnCoS and CoFe-LDH helps to achieve a balance between the adsorption and desorption of intermediate free radicals during the reaction, ultimately improving catalytic activity. The resulting ZnCoS@CoFe-LDH/NF electrode requires only an overpotential of 273 mV at 50 mA cm⁻² for the OER in 1 M KOH electrolyte. Long-term stability is also demonstrated by the ZnCoS@CoFe-LDH/NF electrode, which maintains a constant current density over a 50-hour test. Because of this, the ZnCoS@CoFe-LDH/NF electrode has the potential to be used in industrial settings.