Scalable production of few-layer molybdenum disulfide nanosheets by supercritical carbon dioxide

Molybdenum disulfide (MoS2) has attracted a great deal of attention to its unique properties in recent years. In this work, a scalable and green method was developed for the production of high-quality MoS2 nanosheets using shear-assisted supercritical CO2 exfoliation. Our experiments indicate that high temperature, pressure, and shearing speed are favorable to the exfoliation of MoS2. It is found that over 95% of the exfoliated MoS2 nanosheets are less than 10 layers, among which about 50% are 1-4 layers. Raman spectra and XRD patterns reveal that few-layer MoS2 nanosheets with high planar crystal structure are successfully prepared. Moreover, the produced MoS2 has a better stability in N-methyl-pyrrolidone (NMP) than the bulk MoS2. The concentration of the exfoliated MoS2 in NMP after sedimentation for 7 days is as high as 0.97 mg/ml.