Control of Structure of WSe_x/C Nanocoatings Synthesized via Pulsed Laser Deposition

摘要

The requirements are formulated for a new type of nanomaterials based on transition metal dichalcogenides (TMD), which are promising to create relatively cheap and effective catalysts for electrochemical hydrogen evolution reaction. The possibility of implementation of some important requirements for the structure of these materials is investigated by the example of thin-film coatings containing tungsten dise-lenide and carbon. WSe_x/C coatings are prepared via pulsed laser deposition in an inert and reactive (CH_4) gas in a standard configuration and using an antidroplet screen. In some cases, low DC voltage or pulsed high-voltage bias are applied to the substrate, initiating ion bombardment of the coatings. Factors exerting an important influence on the chemical composition, morphology, and surface topography of the coatings are established. Modes of formation of a rough coating surface with a high density of WSe_2 edges are determined, which is essential for high catalytic activity and performance of TMD-containing nanocatalysts. The carbon phase with a high concentration of sp~2 bonds is needed for effective current transport in the formed layers.