Versatile synthesis of molybdenum sulfide from confined spaces for efficient hydrogen evolution

Abstract

(Quasi-)Amorphous molybdenum sulfide (MoSx) materials with disulfide (S22−) units have superior catalytic activities for hydrogen evolution reaction. However, the structures of the materials are less investigated and diversified. Herein, we first develop a new ethanol-thermal method to prepare MoSx and further apply versatile confined growth treatment with low-cost filler crystallites to efficiently modify its structure and consequent performance. Expectedly, because the material is quasi-amorphous and very deformable, its morphology varies dramatically from granules to foam-like material with specific surface area increases from 22.53 m2/g to 76.24 m2/g under the restriction of confined spaces. Importantly, the amount of S22− units which are responsible for the distinction of MoSx increases as well. By virtue of the confined growth, the catalytic performance of the original material on hydrogen evolution is improved significantly. The over-potential required to obtain 10 mA cm−2 current decreases remarkably from 278 mV to 209 mV and the Tafel slope decreases from 160 mV/decade to 72 mV/decade after confined growth. Therefore, we have proposed an effective method to synthesize and promote the catalytic performance of MoSx.