Few Layers Of Molybdenum Disulfide Nanosheets Produced By Liquid-phase Exfoliation

Molybdenum disulfide?MoS₂?is a two-dimensional layered material with a graphene-like structure.Compared with the bulk molybdenum disulfide,single layer or few layers of MoS₂ nanosheets exhibits unique physical and chemical properties and are widely used in electron device,battery,sensors and so on.The large-quantity preparation of high-quality monolayer or few layers of MoS₂ nanosheets is the precondition for their industrial applications.Among these preparation methods,liquid exfoliation method has shown great potential in the large-quantity preparation of MoS₂.However,the productivity of MoS₂nanosheets prepared by liquid exfoliation method is very low.Therefore,the development of liquid exfoliation with large-quantity and high-quality MoS₂ nanosheets has been attracted great attention.In this work,few layers of MoS₂ nanosheets have need prepared by using intercalation compounds of Sodium tartrate?STDD?or Tetrabutylammonium hydroxide?TBAH?assisted liquid-phase ultrasound exfoliation method or liquid-phase ultrasound exfoliation method in mixed-solvents.The main contents are as follows:?1?MoS₂ nanosheets were prepared in different pure organic solvents N-methyl-2-pyrrolidone?NMP?,N,N-Dimethylformamide?DMF?,Dimethyl sulfoxide?DMSO?,N,N-Dimethylacrylamide?DMAA?,Tetramethylurea?TMU?by liquid-phase ultrasound exfoliation method in the presence of intercalation compound STDD or TBAH.The as-prepared MoS₂ nanosheets were characterized by UV-vis,XRD,Raman,TEM and AFM.The results showed that the addition of intercalation compound in organic solvents enhanced the yields and dispersion concentration of MoS₂ nanosheets,and the MoS₂ nanosheets are few layers?2-5 layers?and belong to 2H-phase MoS₂.?2?The preparation of MoS₂ nanosheets in TMU-H₂O and NMP-H₂O mixed solvents by liquid-phase ultrasonic method is investigated systamatically.The effect of the content of organic solvent in the mixed solvents on the yields and dispersion concentrations of MoS₂ nanosheets was studied.It was found that when the volume fraction of TMU in the TMU-H₂O solvent was 65%,the highest yield and disperse concentration?6.8%,0.475 mg/mL?of MoS₂ nanosheets was obtained,while in NMP-H₂O mixed solvent,the highest yield and disperse concentration of MoS₂ nanosheets was obtained?6.3%,0.220 mg/mL?at the NMP volume fraction of 80%.Compared with pure organic solvents,the disperse concentration of Mo S₂nanosheets in mixed solvents is 4.4 times that in pure organic solvents.In addition,the as-prepared MoS₂nanosheets are 2-5 layers and 2H-phase MoS₂.?3?The preparation of MoS₂ nanosheets in mixed NMP-H₂O solvent with NMP volume fraction of 80%was studied by liquid-phase ultrasound exfoliation method assisted with intercalation compound STDD or TBAH.The effect of intercalation compound,ultrasonic time,and ultrasonic power on the preparation of Mo S₂ nanosheets was analyzed,and the MoS₂ nanosheets were characterized by various techniques.It was shown that the addition of intercalation compound improved the dispersion concentration of the nanosheets by a few times.Furthermore,a few layers?2-5 layers?of MoS₂ nanosheets have been successfully prepared.