Facile and efficient preparation of hemicellulose-assisted MoS2 nanosheets via green liquid-phase exfoliation method

Abstract

A facile, environmental-friendly and efficient exfoliation process has been reported to produce MoS2 nanosheets at room temperature via liquid-phase exfoliation method using hemicellulose as an assistant in aqueous solution. It is found that bulk MoS2 has been successfully exfoliated into few-layered MoS2 nanosheets. The non-polar sites of hemicellulose can firmly adhere to MoS2 surface, whereas the hydrophilic branches can facilitate the dispersion, resulting in the effective exfoliation in aqueous solution. The exfoliated dispersions of MoS2 nanosheets are homogeneous and highly stable over 7 months, even stored at ambient conditions. The optical properties of exfoliated MoS2 nanosheets were investigated by UV–Vis, and the morphological characterizations were examined by SEM, TEM, AFM, XRD and Raman. The results show that the hemicellulose-assisted MoS2 nanosheets produced by 10 mg/ml initial concentration have approximately 8–9 layers. Also, the surface-enhanced Raman scattering (SERS) capability of as-prepared MoS2 nanosheets is observable with the enhancement factor (EF) of about 4 × 104, indicating that the hot-spots can be generated on nanosheets. It demonstrates a plausible application of exfoliated MoS2 nanosheets as a SERS substrate as well as a great potential for other solution-based device fabrication. This present liquid-phase exfoliation method is a green, simple and effective process for mass production of MoS2 nanosheets.