Synthesis and density-functional-theory calculations of electronic band structure of hollow sphere WS₂

A novel and low-cost synthesis of tungsten disulfide (WS₂) transition metal dichalcogenide was carried out via gas-solid reaction in a horizontal quartz reactor. In this process, the prepared hollow WO₃ precursor was sulfided with CS₂ at 550 °C at different durations under N₂ gas atmosphere. The as-prepared WS₂ samples were formed by substitution of O by S during the sulfidation process. The characterization of these samples was performed employing X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET) specific surface area, X-ray photoelectron spectroscopy (XPS) and UV-Vis absorption spectroscopy. The characterization results showed that the as-prepared WS₂ samples were of high quality and purity. No significant differences were observed in various WS₂ samples synthesized during different sulfidation periods. The calculated results obtained from the density functional theory (DFT) indicate that WS₂ has an indirect band gap of ca. 1.56 eV, which is in agreement with experimental band gap of ca. 1.50 eV. Combining the experimental and DFT results suggests that the novel method used in the synthesis of WS₂ has a potential application for large scale production. The obtained WS₂ are of high quality and can be implemented in photocatalysis, catalysis, photovoltaics, optoelectronic devices and photosensor devices.