Phase‐Engineering of 1T/2H Molybdenum Disulfide by Using Ionic Liquid for Enhanced Electrocatalytic Hydrogen Evolution
Xin Zhang, He Li, Hui Yang, Fei Xie, Zhihao Yuan, Lenka Zajı́čková, Wenjiang Li
Abstract
Abstract Two‐dimensional (2D) molybdenum disulfide (MoS 2 ) has been regarded as an attractive non‐precious‐metal electrocatalyst for the hydrogen evolution reaction (HER). Engineering the crystal phase of MoS 2 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‐MoS 2 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 interaction induce the phase transition of MoS 2 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‐MoS 2 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‐MoS 2 with the 1T portion of 91.9 % exhibits a significantly enhanced HER activity compared to that of the MoS 2 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 MoS 2 ‐based electrocatalysts to achieve high HER efficiency.