Xin Zhang, He Li, Hui Yang, Fei Xie, Zhihao Yuan, Lenka Zajíčková, Wenjiang Li
Phase-Engineering of 1T/2H Molybdenum Disulfide by Using Ionic Liquid for Enhanced Electrocatalytic Hydrogen Evolution
ChemElectroChem 7 (2020) 3347-3352
Two-dimensional (2D) molybdenum disulfide (MoS2) has been regarded as an attractive non-precious-metal electrocatalyst for the hydrogen evolution reaction (HER). Engineering the crystal phase of MoS2 to activate the basal planes/edges and simultaneously improve the electronic conductivity is currently an effective strategy for enhancing its HER activity. Herein, we report a facile and efficient hydrothermal route to prepare 1T/ 2H-MoS2 catalysts using ionic liquid (N-butyl pyridinium bromide, [BPy]Br) as a structure-directing agent, where the large steric hindrance of [BPy]Br and the mutual π-stacking inter- action induce the phase transition of MoS2 from 2H to the 1T phase. By adding a suitable amount of [BPy]Br in the reaction system, the portion of the 1T phase in 1T/2H-MoS2 was increased, which can expose more active sites on its basal planes/edges as well as facilitate charge transfer for the HER. Consequently, 1T/2H-MoS2 with the 1T portion of 91.9 % exhibits a significantly enhanced HER activity compared to that of the MoS2 synthesized without the aid of [BPy]Br, in terms of a lower Tafel slope of 59 mV dec-1 . This synthesis strategy provides valuable guidance for designing the phase structure of MoS2 -based electrocatalysts to achieve high HER efficiency.
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