Formation,exfoliation and restacking of MoS 2 nanostructures

Abstract

MoS₂ nanostructures were prepared by heating MoS₃ precursors which were synthesised by acidifying the mixed solution of Na₂MoO₄ and Na₂S or CH₃CSNH₂ (TAA). The formation mechanism and exfoliation restacking behaviours of the obtained MoS₂ nanostructures were investigated. The MoS₃ precursor prepared from TAA was composed of hollow nanoballs while that from Na₂S comprised microsized particles. Heating the obtained MoS₃ hollow nanoballs under H₂ at 780°C led to MoS₂ hollow nanoballs. Owing to high temperatures decreased the layer space of MoS₂, MoS₂ nanoballs were changed into polyhedral structures at 960°C. However, calcining the prepared MoS₃ microsized particles resulted in MoS₂ nanoplatelets both at 780 and 960°C. The prepared MoS₂ nanoballs could exfoliate only partly by the exfoliation technology because of their chemical stability. However, MoS₂ nanoplatelets exfoliated completely in exfoliation treatment and formed nano-MoS₂ monolayer suspension. The restacked production of the obtained nano-MoS₂ monolayer suspension represented similar XRD characteristic with exfoliated nano-MoS₂. This indicated that nano-MoS₂ monolayers did not restack regularly along c axis.