A facile synthesis and characterization of graphene-like WS2 nanosheets

Graphene-like WS2 nanosheets at large scale were successfully synthesized via a facile gas-solid reaction route, using tungsten trioxide (WO3) and thiourea as starting materials, and then calcined at 850 °C under N2 atmosphere for 1 h. The final products were characterized by XRD, EDS, SEM and TEM. TEM and SEM images showed that the thickness of the obtained WS2 nanosheets was ~5 nm. The influence of temperature on the formation of WS2 nanosheets was discussed. A possible three-step conversion mechanism of WS2 nanosheets, which including decomposition, sulfurization, and subsequent exfoliation, was proposed to explain the formation of WS2 nanosheets on the basis of observations of a temperature-dependent morphology evolution process.