Efficient Hydrogen\nand Oxygen Evolution: Dual-Functional\nElectrocatalyst of Zinc Iron Layered Double Hydroxides and Nickel\nCobalt Sulfides on Nickel Foam for Seawater Splitting

Hydrogen, derived from water splitting, holds promise\nas a sustainable\nenergy carrier. However, replacing fossil fuels demands large volumes\nof pure water, a resource that is scarce in numerous regions globally.\nThis study focuses on developing an efficient electrocatalyst for\nseawater splitting, aiming to conserve freshwater resources and overcome\nthe challenges associated with direct utilization of seawater. Zinc\niron layered double hydroxides combined with nickel cobalt sulfides\non nickel foam (ZnFe LDH@NiCoS/NF) are produced to operate efficiently\nin alkaline seawater splitting, which involves the evolution reactions\nof hydrogen and oxygen. Through the utilization of an alkalinized\nelectrolyte and suitable nickel foam substrates, the adverse effects\nof corrosion and chlorine oxidation reactions are effectively mitigated.\nThe composite ZnFe LDH@NiCoS/NF exhibits exceptional electrocatalytic\nefficacy in alkaline seawater, needing remarkably minimal overpotentials\nof 246.3 mV for the hydrogen evolution reaction (HER) and 284.8 mV\nfor the oxygen evolution reaction (OER) to attain the targeted current\ndensity. Additionally, the composite electrocatalyst exhibits decreased\nTafel values of 74.6 mV dec<sup>–1</sup> for the hydrogen evolution\nreaction (HER) and 81.5 mV dec<sup>–1</sup> for the oxygen\nevolution reaction (OER), suggesting enhanced kinetics. This improved\nelectrocatalytic performance is attributed to the increased surface\narea and decreased charge transfer resistance. Additionally, the catalytic\nelectrode exhibits impressive long-term stability, maintaining efficiency\nfor approximately 50 h at a constant current density for both the\nHER and the OER. This study emphasizes the innovative character of\nZnFe LDH@NiCoS/NF as a crucial breakthrough in research on bifunctional\nelectrocatalysts for the HER and the OER, presenting a hopeful direction\nfor harnessing renewable energy from seawater.