Synergistic interfacial dynamics of CoFe-LDH@ZnCo2O4 as robust hybrid heterostructures for sustainable water electrolysis

The development of efficient and stable cobalt-based spinel oxide catalysts is crucial for sustainable and clean energy production through electrocatalytic water splitting . Layered double hydroxides (LDHs) have emerged as a promising class of non-noble metal electrocatalysts for both hydrogen and oxygen evolution reactions . In this study, we report the hybrid heterostructure CoFe-LDH@ZnCo 2 O 4 on a self-supported nickel foam substrate (ZCF-LDH/NF) using a cost-effective two-step hydrothermal process. The robust interfacial network and abundant catalytically active sites of ZCF-LDH/NF facilitate efficient charge transfer. The resulting ZCF-LDH/NF catalyst exhibits remarkable bifunctional electrocatalytic activity , achieving low overpotentials of approximately 290 mV and 296 mV for the oxygen evolution reaction (OER) and 195 mV and 208 mV for the hydrogen evolution reaction (HER) at a current density of 50 mA cm −2 in both fresh and simulated alkaline seawater , respectively. Additionally, the integrated water electrolyzer featuring ZCF-LDH/NF (−) ‖ZCF-LDH/NF (+) electrodes demonstrates impressive performance, requiring only 1.61 V to reach 10 mA cm −2 in alkaline and 1.64 V in simulated alkaline conditions. Further, Mott–Schottky analysis reveals the semiconductor properties and flat-band potentials of the components, providing insights into the charge transfer mechanisms. First-principles density functional theory calculations unveil the creation of more active sites on the CoFe-LDH surface, contributing to the heterostructure's overall catalytic activity . Notably, this work presents spinel oxide/LDH-based heterostructures as efficient and cost-effective catalysts with negligible catalytic activity loss, offering great potential for sustainable hydrogen production and energy conversion applications. • CoFe-LDH@ZnCo 2 O 4 /NF catalyst was synthesized via a two-step hydrothermal method. • Interfacial engineering boosts charge transfer and enhances OER/HER activity. • Mott-Schottky analysis confirms favorable band alignment for charge migration. • ZCF-LDH/NF electrolyzer requires 1.61 V (alkaline) and 1.64 V (seawater) at 10 mA cm −2 with high stability. • DFT reveals interfacial charge redistribution that optimizes electronic structure and boosts catalytic performance.