Ultrathin WS2 nanosheets vertically aligned on TiO2 nanobelts as efficient alkaline hydrogen evolution electrocatalyst

Highly efficient and durable non-noble metal-based hydrogen evolution electrocatalysts are critical to advance the production of hydrogen energy via alkaline water electrolysis. Herein, we prepared a novel TiO2@WS2 hybrid via a facile and scalable two-step hydro thermal strategy combined with selective etching. Benefited from acid-etched TiO2 nano belts with rough surface as substrate, ultrathin WS2 nanosheets nucleated and vertically grew into few layers in the confined configuration with more exposed active edges. Furthermore, the partial incorporation of oxygen in WS2 inherited from the remaining O-W bonds of tungsten precursor enhanced the electrical conductivity of the hybrid. Therefore, TiO2@WS2 hybrid was proved to be efficient and durable electrocatalyst for hydrogen evolution in alkaline medium. Upon optimal conditions, the hybrid only required a small onset overpotential of 95 mV and a low overpotential of 142 mV at 10 mA cm(-2), superior to pristine WS2 and TiO2. In addition, better cycling stability during the alkaline HER process was also obtained, indicating its capability in future practical application. The synthesis strategy presents a cost-effective approach to produce efficient WS2-based HER electrocatalyst for electrochemical water splitting. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.