Nature Chemistry 2018-04-02

High phase-purity 1T′-MoS2- and 1T′-MoSe2-layered crystals

Yifu Yu, Gwang-Hyeon Nam, Qiyuan He, Xue-Jun Wu, Kang Zhang, Zhenzhong Yang, Junze Chen, Qinglang Ma, Meiting Zhao, Zhengqing Liu, Fei-Rong Ran, Xingzhi Wang, Hai Li, Xiao Huang, Bing Li, Qihua Xiong, Qing Zhang, Zheng Liu, Lin Gu, Yonghua Du, Wei Huang, Hua Zhang

Index: 10.1038/s41557-018-0035-6

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Abstract

Phase control plays an important role in the precise synthesis of inorganic materials, as the phase structure has a profound influence on properties such as conductivity and chemical stability. Phase-controlled preparation has been challenging for the metallic-phase group-VI transition metal dichalcogenides (the transition metals are Mo and W, and the chalcogens are S, Se and Te), which show better performance in electrocatalysis than their semiconducting counterparts. Here, we report the large-scale preparation of micrometre-sized metallic-phase 1T′-MoX2 (X = S, Se)-layered bulk crystals in high purity. We reveal that 1T′-MoS2 crystals feature a distorted octahedral coordination structure and are convertible to 2H-MoS2 following thermal annealing or laser irradiation. Electrochemical measurements show that the basal plane of 1T′-MoS2 is much more active than that of 2H-MoS2 for the electrocatalytic hydrogen evolution reaction in an acidic medium.