Novel WS₂-Based 3D Electrode with Protecting Scaffold for Efficient and Stable Hydrogen Evolution

The synthesis of an efficient and stable WS 2 -based three-dimensional (3D) electrode remains a challenge. Herein, a novel WS 2 -based 3D electrode (WS 2 /graphite rods (GR)) with significantly advanced electrocatalytic hydrogen evolution activity and stability was demonstrated. Compared to the film electrode of powdery WS 2, WS 2 /GR showed a much lowered contact resistance (∼1 Ω), leading to a 200 mV lowered overpotential and a Tafel slope (47.9 mV·dec –1 ) much closer to that of the Pt electrode. Meanwhile, the novel 3D electrode exhibited greatly improved stability with little current decay after 15 h reaction. Further investigation revealed three different morphologies of WS 2 nanostructures on and into the graphite rod. While the vertically growing WS 2 nanosheets and WS 2 nanoparticles inside played essential roles in advanced activity, the densely stacked ball-like self-assemblies of WS 2 nanosheets on the surface of the rod was of little importance for the hydrogen evolution reaction performance. The reasons were that the confinement effect and the well protection of the graphite scaffold allowed the WS 2 nanostructures inside the rod with largely exposed active sites and less likely to be oxidized. The work not only achieved excellent WS 2 -based 3D electrode but also provided effective approach for synthesizing efficient and stable 3D electrodes.