Metallic 1T-phase MoS2 is considered to be the ideal electrocatalyst to carry out hydrogen evolution reaction (HER) because of favorable conductivity and sufficient active site compared with 2H-phase MoS2. Nevertheless, 1T-phase MoS2 is conventionally synthesized in a complicated process, with the production of an unstable product, which hinders their practical applications. Herein, we propose a facile approach through a carbon-doping-induced phase transition to obtain highly stable 1T-2H mixed MoS2 nanosheets. The phase transition process is characterized by Raman and X-ray photoelectron spectroscopy, as well as high-resolution transmission electron microscopy images and delivers a high phase purity of ∼60% for 1T-MoS2. According to density functional theory simulations and experimental results, C-doped 1T-2H mixed MoS2 has the advantages of abundant active sites, facilitated charge transfer rate, and high activity toward HER. The obtained C-doped MoS2 exhibits a superb HER electrocatalytic performance, with a current density of 10 mA cm-2 and the overpotential as low as 40 mV in 1 M KOH solution, and brilliant stability.

中文翻译：

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MoS2的深相变，通过便捷的C掺杂策略实现出色的氢释放反应。

与2H相MoS2相比，金属1T相MoS2具有良好的电导率和足够的活性中心，因此被认为是进行氢释放反应（HER）的理想电催化剂。然而，传统上以复杂的过程合成1T相MoS 2，产生不稳定的产物，这阻碍了它们的实际应用。在本文中，我们提出了一种通过碳掺杂诱导的相变的简便方法，以获得高度稳定的1T-2H混合MoS2纳米片。相变过程的特征在于拉曼光谱和X射线光电子能谱，以及高分辨率的透射电子显微镜图像，可为1T-MoS2提供约60％的高相纯度。根据密度泛函理论模拟和实验结果，掺C的1T-2H混合MoS2具有活性部位丰富，电荷转移速率快，对HER活性高的优点。所得的C掺杂MoS2表现出极好的HER电催化性能，电流密度为10 mA cm-2，在1 M KOH溶液中的过电势低至40 mV，并且具有出色的稳定性。