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

The synthesis of an efficient and stable WS2-based three-dimensional (3D) electrode remains a challenge. Herein, a novel WS2-based 3D electrode (WS2/graphite rods (GR)) with significantly advanced electrocatalytic hydrogen evolution activity and stability was demonstrated. Compared to the film electrode of powdery WS2, WS2/GR showed a much lowered contact resistance (similar to 1 Omega), 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 WS2 nanostructures on and into the graphite rod. While the vertically growing WS2 nanosheets and WS2 nanoparticles inside played essential roles in advanced activity, the densely stacked ball-like self-assemblies of WS2 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 WS2 nanostructures inside the rod with largely exposed active sites and less likely to be oxidized. The work not only achieved excellent WS2-based 3D electrode but also provided effective approach for synthesizing efficient and stable 3D electrodes.