MoS<sub>2</sub> Nanoflowers Grown on Plasma‐Induced W‐Anchored Graphene for Efficient and Stable H<sub>2</sub> Production Through Seawater Electrolysis
Van Dien Dang, P. Raghunath, M. C. Lin, Kung‐Hwa Wei
Abstract
Abstract 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.