Facile access to shape-controlled growth of WS2 monolayer via environment-friendly method

2D materials with tailored morphologies exhibit distinctive shape-dependent properties especially in electrocatalysis and gas sensing, extending their applications in nanoelectronics. Atomic-layer tungsten disulfide (WS2) stands out as a promising candidate, but the controllable synthesis of WS2 still faces unavoidable obstacles, such as strict parameter requirements, low efficiency and serious pollution during the preparation. Here we report an elegant technique for growing homogeneous-luminescence WS2 monolayer with desired shapes and developed electrochemical properties, through the improved chemical vapor deposition method with a semi-closed airflow environment. It is an effective, economic and especially environment-friendly approach with atmospheric pressure and hydrogen-free condition, aiming at synthesizing high-quality and large-scale monolayer WS2 crystals with only one heating zone. Compared with the existing methods, this one significantly minimizes the sulphur contamination to the environment and equipment, enabling the reuse of quartz tube and reducing the cost. More importantly, different shapes of WS2 domains with high crystalline and excellent homogeneity of luminescent intensity are controllable by adjusting the growth temperatures. In addition to the good electrical transport performance of WS2 monolayer, the WS2 domains with different morphologies exhibit modulated properties for catalyzing the electrochemical hydrogen evolution. This systematic study on shape-controlled growth and shape-dependent electrochemical performances of WS2 will further push forward their practical applications.