Preparation And Characterization Of NH₄～+-Intercalated Molybdenum Disulfide

Molybdenum disulfide is one kind of inorganic materials with lamellar structure. Several intercalation compounds of molybdenum disulfide containing various guest substances with photic, electrical, magnetic, thermal or catalytical properties were prepared in order to get novel desired functions.The method used for synthesizing the molybdenum disulfide (MoS₂) intercalated by ammonium cation (NH₄⁺)xMoS₂ was based on the exfoliation/restacking process of Li_xMoS₂. The Li-intercalation compound of MoS₂ was completed by n-butyl lithium and MoS₂. It was obtained that a stable aqueous dispersion of monolayer MoS₂ by the strong hydrolysis of crystalline Li_xMoS₂ with water. By the use of the mixed reaction of ammonium chloride solution and the monolayer of molybdenum disulfide, the intercalation compounds of MoS₂ with inorganic ammonium cation could be obtained. The space between MoS₂ was detected using XRD and was increased from 0.615nm to 0.954nm. When the intercalation compounds were added to the solution of NaOH, it was found that the ammonia was escaped when they were heated. The x value of the intercalation compound was determined to be 3 by elemental analysis and TGA.In addition, the experiment conditions were optimized by using the single factor and orthogonal experimental design methods based on the space variation of the intercalation compound. The optimal experimental conditions are as follows: 1.0 wt% ammonium chloride solution concentration, 35°C reactive temperature and 8 hour reactive time. Under this condition the (NH₄⁺)_xMoS₂ intercalation compound with largest layer space of 0.9928nm could be got.When the intercalation compounds were saved in air for three months, there was not any change through the results from the analysis of XRD. The intercalated material was reverted to the monolayer molybdenum disulfide after heated with NaOH.The 1,4-Butanediol/MoS₂ intercalation compound was prepared by the method of exfoliation and restacked process. The result showed the 1,4-Butanediol was intercalated into the layers of MoS₂. The role of the added acid in the procedure was to neutralize the LiOH by-product. The acid also helped in inducing restacking process of the exfoliated MoS₂ by lowering pH value.