Oxygen mediated growth of flower-like tungsten disulfide nanosheets as highly active photocatalysts

The synthesis of graphene-like transition metal dichalcogenides (TMDs) has attracted great attention because of its excellent photoelectric properties and wide potential applications. Well controlling the preparation and understanding the growth mechanism of these nanomaterials are important for the development of applications with high efficiency. In this paper, we synthesized flower-like tungsten disulfide nanosheets (F-WS 2 ) by reacting tungsten oxide with sulfur vapor. Lots of thin WS 2 nanosheets with a thickness of a few nanometers are assembled together from the same center to form a flower-like microsphere with a diameter of ~ 1–4 µm. These nanostructures have been characterized by various techniques, and the growth mechanism has been investigated. The flow rate of oxygen (or atmosphere with oxygen) is found to play a key role in the growth to mediate the morphology to obtain these flower-like WS 2 nanosheets, while only WS 2 nanoparticles (N-WS 2 ) are grown without oxygen flow. These F-WS 2 show excellent photocatalytic activities, which are also better than those of N-WS 2 . So this method confirms the feasibility of oxygen regulated growth of similar TMDs materials, which is also important for the development of photocatalysts with high efficiency.