Few-Layered WS2 Anchored on Co, N-Doped Carbon Hollow Polyhedron for Oxygen Evolution and Hydrogen Evolution

Tungsten disulfide (WS2) is well known to have great potential as an electrocatalyst, but the practical application is hampered by its intrinsic inert plane and semiconductor properties. In this work, owing to a Co-based zeolite imidazole framework (ZIF-67) that effectively inhibited WS2 growth, few-layered WS2 was confined to the surface of Co, N-doped carbon polyhedron (WS2@Co9S8), with more marginal active sites and higher conductivity, which promoted efficient oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). For the first time, WS2@Co9S8 was prepared by mixing in one pot of a liquid phase and calcination, and WS2 realized uniform distribution on the polyhedron surface by electrostatic adsorption in the liquid phase. The obtained hybrid catalyst exhibited excellent OER and HER catalytic activity, and the OER potential was only 15 mV at 10 mA cm-2 higher than that of noble metal oxide (RuO2). The improvement of catalytic activity can be attributed to the enhanced exposure of sulfur edge sites by WS2, the unique synergistic effect between WS2 and Co9S8 on the metal-organic framework (MOF) surface, and the effective shortening of the diffusion path by the hollow multi-channel structure. Therefore, the robust catalyst (WS2@Co9S8) prepared by a simple and efficient synthesis method in this work will serve as a highly promising bifunctional catalyst for OER and HER.