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.

相控制在无机材料的精确合成中起着重要作用，因为相结构对诸如电导率和化学稳定性等性质具有深远的影响。对于金属相-VI族过渡金属二卤化物（过渡金属为Mo和W，硫族元素为S，Se和Te）而言，相控制备一直具有挑战性，它们在电催化方面的表现优于半导体。这里，我们报告微米级金属相1T的大规模制备' -MoX ₂（X = S，Se）的高纯度-layered块状晶体。我们揭示了1T'-MoS ₂晶体具有扭曲的八面体配位结构并且可以转换为2H-MoS ₂热退火或激光辐照之后。电化学测量表明，在酸性介质中，1T'-MoS ₂的基面比2H-MoS ₂的基面具有更高的活性。