NiMo LDH-Derived Mo@NiSe₂ as Advanced Electrocatalysts for Hydrogen Evolution in Acidic and Alkaline Systems

The growing global energy crisis and environmental challenges demand clean and renewable energy solutions. Hydrogen is a promising alternative to fossil fuels due to its high energy density and zero-emission characteristics when used as a fuel. However, efficient hydrogen production through electrochemical water splitting, which involves both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), requires highly efficient electrocatalysts to achieve lower overpotentials and accelerate the reaction kinetics. In this study, we report the selenization of NiMo layered double hydroxide (NiMo LDH) to form Mo-doped nickel selenide (Mo@NiSe2) through a simple solvothermal process. This structural modification significantly enhances the electrocatalytic activity for HER. The resulting Mo@NiSe2 exhibit remarkable improvement in HER performance, with Mo@NiSe2 achieving an overpotential of 118 mV at 10 mA/cm2, compared to the 602 mV required by the pristine NiMo LDH. This enhancement is attributed to the modified d band electronic structure, which increases electron conductivity along with surface area that induces a greater number of active sites on the catalyst. Theoretical DFT studies showed an absolute ΔGH value of 0.02 eV for Mo@NiSe2 (210), substantiating the higher electrochemical HER activity. These findings suggest that the transformation of NiMo LDH into its selenide form is a viable strategy for developing low-cost, efficient electrocatalysts for hydrogen production, contributing to the advancement of sustainable energy technologies.