Synthesis Of Two-Dimensional Transition Metal Dichalcogenides And Their HER Activities

Recently, two-dimensional (2D) layered materials have drawn a great deal of attentions due to their remarkable physical and chemical properties. For example, with intensive study for decades, graphene has already been applied to industrial developments. As a number of 2D layered materials family, transition metal dichalcogenides (TMDCs) have already exhibited intriguing properties and application potential in aspects such as field effect transistor, optoelectronic devices, topological insulators and electrocatalysts. Chemical vapor deposition (CVD) has become a major approach towards 2D TMDCs synthesis because of its simplicity of operator and relatively low cost. But the exploration of a stable approach to obtain high quality TMDCs materials remains an urgent demand yet. Meanwhile, the unique crystal structure of 2D TMDCs brings out extremely high specific surface area and excellent electronic transmission abilities, make its performance in hydrogen evolution reaction (HER) worth expecting. In such time when people are zealously looking for alternative energy sources, the research on such new-emerging materials is absolutely imperative and with great significance.In this paper, our work focuses on following aspects:(1) We proceeded an in-depth study of the synthesis of TMDCs materials via CVD method, with tungsten disulfide as an example, and we systematically analyzed and discussed the impact of various experiment parameters based on a large number of experimental data.(2) Upon our profound understanding on TMDCs materials synthesis via CVD method, we successfully realized the synthesis of monolayer WS2(1-x)Se2X, and elaborately revealed its physical and chemical properties with a series of characterization methods.(3) The as-synthesized monolayer WS2(1-x)Se2X was utilized as a catalyst in HER, and its performance was measured in a series of experiments. The catalytic mechanism of the catalysts was studied and discussed, based on the characterization and comparison of HER performances of samples with different x values.