Large-Scale Monolayer VS₂ as Catalyst for Hydrogen Evolution Reaction

Two-dimensional (2D) layered transition metal dichalcogenides have garnered significant attention for their potential in advanced applications of electronics and energy conversion technologies. As a prototypical member of the 2D materials family, vanadium disulfide (VS2) distinguishes itself through its great mechanical strength, tunable electronic characteristics, intriguing magnetic properties, and exceptional electrochemical performance. However, the synthesis of high-quality VS2 films is severely hampered by its thermodynamic instability and the tendency to form polymorphs. In this work, we present clean and efficient low-pressure chemical vapor deposition for the growth of large-scale H-phase VS2 monolayers on sapphire substrates. By regulating the ratio of precursors, controlling the growth temperature and optimizing the position of substrates, the production of polymorphs is effectively suppressed, resulting in improved quality of VS2 films. Electrochemical measurements reveal that the VS2 monolayers exhibit superior electrocatalytic performance for hydrogen evolution reaction compared to monolayer molybdenum disulfide (MoS2). This work provides a significant advancement in the scalable production of monolayer VS2 and its potential applications in clean energy technologies.