Two-step hydrothermal synthesis of Mo-Ni3S2@NiFe LDH/NF three-dimensional walnut-like nanostructured bifunctional electrocatalysts for efficient overall water splitting

Abstract

The design of novel composite nanomaterial structures is critical for developing advanced electrocatalysts. However, obtaining new electrocatalysts that are low-cost, highly active, and stable remains challenging. This paper presents the synthesis of Mo-Ni₃S₂@NiFe LDH/NF electrocatalysts on nickel foam substrates via a hydrothermal method. The resulting catalysts exhibit a unique three-dimensional walnut shell nanostructure, which enhances electron transfer, provides abundant active sites, and promotes gas release. The Mo-Ni₃S₂@NiFe LDH/NF catalyst shows exceptional catalytic activity for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). With an OER overpotential of 331 mV at 80 mA·cm⁻² and a HER overpotential of 153 mV at 10 mA·cm⁻², it demonstrates high efficiency, positioning it as a promising candidate for energy conversion applications, including water splitting. Meanwhile, the catalyst exhibited an excellent performance of 1.57 V at 10 mA·cm⁻² current density under the two-electrode structure. The Mo-Ni₃S₂@NiFe LDH/NF catalyst exhibits exceptional catalytic activity and stability due to its unique structural features and the synergistic interaction between Mo-Ni₃S₂ and NiFe LDH. This interaction reduces charge transfer resistance, enhancing performance for high-efficiency, long-term water splitting applications. In conclusion, the proposed method for developing low-cost, efficient, and stable bifunctional electrocatalysts holds strong promise for advancing hydrogen energy conversion, offering a viable path toward large-scale and sustainable hydrogen production.