MoS 2 Nanoflowers Grown on Plasma-Induced W-Anchored Graphene for Efficient and Stable H 2 Production Through Seawater Electrolysis.

Herein, it is found that 3D transition metal dichalcogenide (TMD)-MoS ₂ nanoflowers-grown on 2D tungsten oxide-anchored graphene nanosheets (MoS ₂ @W-G) functions as a superior catalyst for the hydrogen evolution reaction (HER) under both acidic and alkaline conditions. The optimized weight ratio of MoS ₂ @W-G (MoS ₂ :W-G/1.5:1) in 0.5 M H ₂ SO ₄ 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 MoS ₂ @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 MoS ₂ @W-G structure model confirm that suitable hybridization of 3D MoS ₂ and 2D W-G nanosheets can lower the hydrogen adsorption: Gibbs free energy (∆G _H* ) from 1.89 eV for MoS ₂ to -0.13 eV for the MoS ₂ @W-G composite. The excellent HER activity of the 3D/2D hybridized MoS ₂ @W-G composite arises from abundance of active heterostructure interfaces, optimizing the electrical configuration, thereby accelerating the adsorption and dissociation of H ₂ O. These findings suggest a new approach for the rational development of alternative 3D/2D TMD/graphene electrocatalysts for HER applications using seawater.
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