Three-Dimensional NiCo2S4/MoS2 Heterostructured Nanoflakes on Nickel Foam as a High-Performance Electrocatalyst for Alkaline Hydrogen Evolution Reaction

Abstract The development of cost-effective, high-performance electrocatalysts for the alkaline hydrogen evolution reaction is imperative for sustainable hydrogen production via water electrolysis. However, the intrinsically sluggish reaction kinetics and insufficient exposed active sites of transition metal sulfides remain critical bottlenecks. Herein, we report the facile hydrothermal synthesis of binder-free, three-dimensional NiCo2S4/MoS2 heterostructured nanoflakes directly grown on nickel foam as a highly efficient electrocatalyst for alkaline hydrogen evolution. Benefiting from the synergistic effects between NiCo2S4 and MoS2, which provide abundant active edge sites, enhanced electrical conductivity, and reinforced structural stability, the as-prepared NiCo2S4/MoS2 electrode exhibits excellent activity in alkaline media, requiring an ultralow overpotential of only 112 mV to achieve a current density of 10 mA cm–2. Moreover, the electrode demonstrates remarkable long-term durability. The superior hydrogen evolution performance originates from the rational integration of NiCo2S4 and MoS2 within the unique heterostructure, offering a promising strategy for designing other robust transition metal sulfide-based electrocatalysts.