Synthesis Of MoS₂ By Hydrothermal Method And Investigation For Its Photo-catalytic Properties

Molybdenum disulfide(MoS2)is the main component of molybdenite,and has the same layered structure with graphene.Molybdenum disulfide nano-materials are also widely used in the field of tribology,electrochemical fields ect.Molybdenum disulfide has a band gap of 1.78 eV,and has a large specific surface area,therefore,molybdenum disulfide in the field of visible light has a wide range of applications.At present,there are many kinds of methods for preparing molybdenum disulfide,such as molybdenum disulfide prepared by mechanical exfoliation,and the molybdenum disulfide powder with different morphology is prepared by controlling the reaction conditions by vapor deposition method.Preparation of molybdenum disulfide of different sizes by reduction of ammonium tetrathiomolybdate precursor.However,the photocatalytic efficiency of molybdenum disulfide powder in the field of specific photocatalysis such as hydrogen production is still low,mainly because of the poor dispersibility of molybdenum disulfide powder and the use of solar radiation band narrow.If the hydrophilic organic modified molybdenum disulfide particles can be prepared to prevent the agglomeration between particles,the formation of soluble molybdenum disulfide colloid,and in the surface load to expand the use of solar radiation band of terpyridine ruthenium photo sensitizer,can effectively improve the photocatalytic performance of molybdenum disulfide.In this paper,colloidal molybdenum disulfide was prepared by two-step hydrothermal method.Formamidino thiomide precursor was prepared by using ammonium molybdate and thiourea as molybdenum source and sulfur source respectively and reduction of formamidine thiomide precursors with hydrazine hydrate.In the preparation process,the precursors and products were analyzed by UV and fluorescence spectroscopy.The effects of hydrothermal reaction temperature,hydrothermal reaction time,material ratio on the precursor and the product were explored.The optimum reaction temperature is 140 ?,the reaction time is 24 h,the ratio of molybdenum to sulfur is 1: 4 for the preparation of precursor.When the molybdenum disulfide is prepared by reducing the precursor,the optimum reaction temperature is 100 ?,the reaction time is 4 h,the ratio of molybdenum to nitrogen is 1:12.Finally,the colloidal molybdenum disulfide was sensitized by terpyridine ruthenium chloride sensitizer.In order to fing out the photocatalytic performance and photo-sensitization of colloidal molybdenum disulfide,the photocatalytic degradation experiment was carried out with coomassie brilliant blue as photocatalytic degradation object.The experimental results show that the prepared colloidal molybdenum disulfide has a visible photocatalytic effect,but the catalytic efficiency is generally improved by the visible light photocatalytic efficiency of colloidal molybdenum disulfide,which is sensitized by triclopidyl chloride.The photocatalytic effect of colloidal molybdenum disulfide is related to the concentration of photosensitizer,and the catalytic efficiency increases with the increase of the load concentration,but the high concentration of the catalyst is reduced.