Synthesis of NiSe₂@M (M=Cu, Fe and Zn)-NiCo LDH with porous structure on nickel foam for overall fresh and seawater splitting

We report the preparation of NiSe2@M (M = Cu, Fe, and Zn)-NiCo LDH catalysts with a porous structure composed of nanospheres loaded with nanosheets on a nickel foam substrate using a hydrothermal method. The designed NiSe2@Fe-NiCo LDH catalysts exhibit excellent performance in both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline freshwater and seawater electrolytes. For OER, a current density of 10 mA cm-2 is achieved with only a 260 mV overpotential, while for HER, 10 mA cm-2 is attained with only a 130 mV overpotential. These catalysts maintain good stability in alkaline freshwater and seawater environments. Density functional theory (DFT) analyses indicate that the Fe-NiCo LDH electrode has the optimal Gibbs free energy, underscoring its catalytic role. The introduction of NiSe2 enhances the electrical conductivity of the NiSe2@Fe-NiCo LDH electrode. The synergistic catalysis of NiSe2 and Fe-NiCo LDH contributes to the superior catalytic performance of the electrode. This work offers a novel approach to explore efficient and stable non-precious metal-doped catalysts for freshwater and seawater splitting.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.