Designed Synthesis And Performance Research Of Molybdenum Disulfide Nanomaterials

Nanomaterials have a wide range of fields in biosensors,photocatalysis,electrochemical catalysis,material engineering,environmental engineering,energy conversion and storage,biomedicine,etc.due to their unique structures and their unique physical and chemical properties.Application and show good performance.In recent years,transition metal disulfides(TMDs)are a highly sought-after material in academia and industry,because these materials have a spatial structure very similar to graphene,making it similar to graphene in terms of application..However,TMDs are typical semiconductors,which are different from the unique properties of graphene,which also makes them have great application prospects in the field of optoelectronics.Among many TMDs,molybdenum disulfide(MoS₂)is a material with extremely excellent performance,especially MoS₂ nanomaterials.As a functional nanomaterial,nano-MoS₂ has a broad application prospect in many fields such as lubricants,composite materials,catalytic materials,secondary batteries,hydrogen storage materials,transistors,sensors and optoelectronic devices.Compared with MoS₂ in bulk structure,Nano MoS₂ has a great improvement in application performance,in particular:reduced friction coefficient,greatly improved lubricating capacity,increased specific surface area,enhanced adsorption capacity,increased reactivity and catalytic performance Enhancement,etc.In view of the shortcomings of the current MoS₂ nanomaterial preparation methods,such as low product purity,uncontrollable morphology and complicated preparation process,we conducted relevant research on the design,synthesis and performance of MoS₂ nanomaterials,and achieved some stage results:(1)Design and synthesis of MoS₂ nanomaterials:We synthesized a series of MoS₂ nanomaterials by liquid phase method.The effects of experimental factors such as heating method,reaction time,molybdenum source type,sulfur source type,reactant concentration and solvent type on MoS₂ nanomaterials were systematically studied.The study found that the heating method,reaction time,type of molybdenum source,type of sulfur source and the concentration of reactants have a greater influence on the morphology of MoS₂ nanomaterials.The advantages and disadvantages of different heating methods(liquid phase method,solvothermal method and microwave liquid phase method)were systematically studied.The solvothermal reaction time is too long,and the crystal growth time is too long,which makes the size of the nanomaterials larger;the morphology of the MoS₂ nanomaterials prepared by the microwave liquid phase method is extremely irregular,which is caused by the rapid heating rate of microwave heating.Compared with the first two heating methods,the liquid phase method has low environmental requirements,simple operation method,and the prepared MoS₂nanomaterial has good morphology and is easy to control.In the liquid phase preparation process,there is no product when the reaction time is less than 2 h,and the product agglomerates when the reaction time is longer than 6 h.The morphology of the nanomaterials prepared when the reaction time is about 4 h is optimal.When sodium molybdate dihydrate(Na₂Mo O₄·2H₂O)is used as the molybdenum source,no solid product is produced when the molybdenum-sulfur ratio is in the range of 7:4-7:8,and when the molybdenum-sulfur ratio is in the range of 7:16-7:32 MoS₂ products are sometimes produced,but the morphology of the resulting MoS₂ is irregular.In contrast,when using ammonium molybdate tetrahydrate((NH₄)₆Mo₇O₂₄·4H₂O)as the source of molybdenum,the morphology of the prepared MoS₂ product is more regular.It shows that the type of molybdate has an important influence on the morphology of MoS₂material.MoS₂ nanomaterials can be prepared with elemental sulfur and thiourea(H₂NCSNH₂)as the sulfur source,but the nanomaterials prepared with elemental sulfur as the sulfur source have a more regular morphology and a smaller degree of agglomeration.The concentration of the reactants also has a greater influence on the morphology of the MoS₂ nanomaterials.At a higher molybdenum source concentration((NH₄)₆Mo₇O₂₄·4H₂O dosage is 1.0 g),no matter how the sulfur source dosage is adjusted,the particle size of the prepared MoS₂ nanomaterial Both are large and irregular in appearance.At a lower molybdenum source concentration(the dosage of(NH₄)₆Mo₇O₂₄·4H₂O is 0.1 g),a series of controllable MoS₂ nanospheres can be obtained by adjusting the dosage of the sulfur source(elemental sulfur).(2)Application performance study of MoS₂ precursors and MoS₂ nanospheres:We tested the ability of the prepared MoS₂ nanospheres and MoS₂ precursors to degrade dyes and Cr(?).We added 10 mg of catalyst to 50 m L of methylene blue(MB)dye solution(10 mg/L)and 50 m L of Cr(VI)solution(10 mg/L),and started dark reaction experiment and photocatalysis experiment.We found that when three MoS₂ precursors with a molybdenum-sulfur ratio of 7:8,7:16,and 7:32 were used in the dye degradation experiment,the catalyst had completely absorbed the dye after 5 minutes of ultrasonic treatment.It can be seen that the MoS₂ precursor has extremely excellent adsorption performance.It can be seen from the degradation curve of the raw material molybdenum-sulfur ratio 7:4 precursor that the sample reaches saturation after5 minutes of ultrasound adsorption,and then steadily and completely degrade the dye in the photocatalytic reaction.In the dark reaction stage,the adsorption rate of the prepared MoS₂precursors to Cr(VI)is about 60%,indicating that these materials have similar adsorption capacity for Cr(VI).However,in the photocatalytic reaction stage,the performance of the MoS₂precursor prepared with a molybdenum-sulfur ratio of 7:16 is obviously due to the other two.After exposure to light for 3 h,there is almost no Cr(?)in the solution.MoS₂ nanosphere degradation MB dye solution is nearly saturated after 5 minutes of ultrasound,but there is still a very weak adsorption process in the dark reaction stage.The photocatalytic degradation performance of MoS₂ obtained after calcination at high temperature is better than that of the precursor,and the molybdenum-sulfur ratio The photocatalytic performance of 7:16 MoS₂ is the best.(3)Preparation and performance study of the MoS₂/g-C₃N₄ composite material:we mixed the prepared MoS₂ precursor with melamine(C₃N₃(NH₂)₃)in proportion,then reacted at high temperature in a tube furnace,and obtained MoS₂/g-C₃N₄ composite material,through the characterization and performance of this composite material,we found that the MoS₂ we prepared effectively interfered with the morphology of g-C₃N₄,and greatly improved the photocatalysis of g-C₃N₄ Reactivity.