MoS2 Nanoflowers Grown on Plasma‐Induced W‐Anchored Graphene for Efficient and Stable H2 Production Through Seawater Electrolysis

Herein, it is found that 3D transition metal dichalcogenide (TMD)—MoS2 nanoflowers—grown on 2D tungsten oxide‐anchored graphene nanosheets (MoS2@W‐G) functions as a superior catalyst for the hydrogen evolution reaction (HER) under both acidic and alkaline conditions. The optimized weight ratio of MoS2@W‐G (MoS2:W‐G/1.5:1) in 0.5 M H2SO4 achieves a low overpotential of 78 mV at 10 mA cm–2, a small Tafel slope of 48 mV dec–1, and a high exchange current density (0.321 mA cm⁻2). Furthermore, the same MoS2@W‐G composite exhibits stable HER performance when using real seawater, with Faradaic efficiencies of 96 and 94% in acidic and alkaline media, respectively. Density functional theory calculations based on the hybrid MoS2@W‐G structure model confirm that suitable hybridization of 3D MoS2 and 2D W‐G nanosheets can lower the hydrogen adsorption: Gibbs free energy (∆GH*) from 1.89 eV for MoS2 to –0.13 eV for the MoS2@W‐G composite. The excellent HER activity of the 3D/2D hybridized MoS2@W‐G composite arises from abundance of active heterostructure interfaces, optimizing the electrical configuration, thereby accelerating the adsorption and dissociation of H2O. These findings suggest a new approach for the rational development of alternative 3D/2D TMD/graphene electrocatalysts for HER applications using seawater.