MoS₂/NiCo-LDHs Composite: Hydrothermal Synthesis of a Bifunctional Electrocatalyst for Efficient Overall Water...

To effectively combat global energy demands, the development of bifunctional electrocatalysts exhibiting both superior stability and low cost is essential for enabling sustainable water splitting. In this study, NiCo-LDHs nanosheets were synthesized on flower-like MoS₂ nanostructures using a rational two-step hydrothermal method. By adjustment of the MoS₂ content, the composite morphology evolved from layered intercalation to three-dimensional flower-like aggregates. High-resolution transmission electron microscopy (HRTEM) imaging revealed stable heterointerfaces formed via interfacial coupling. X-ray photoelectron spectroscopy (XPS) analysis indicated that robust interfacial electronic interactions induce multivalent states of Mo and S, enhancing the density of active sites. The 200-MoS₂/NiCo-LDHs electrocatalyst demonstrated bifunctional activity after optimization. In the 1 M KOH electrolyte, the catalyst exhibited low overpotentials of 183 mV for HER and 334 mV for OER at 10 mA cm^-2, while achieving an overall water splitting voltage of 1.657 V. This configuration exhibits remarkable stability, maintaining performance for over 100 h during continuous operation. Complementary density functional theory (DFT) calculations showed charge redistribution at the heterointerface. The reduced bandgap (0.628 eV) greatly improves interfacial charge transfer kinetics, underscoring the synergistic effect.