Design And Synthesis Of Molybdenum Disulfide Nanospheres And Their Potential Applications In Photothermal Therapy Of Tumors And Hydrogen Production From Photolysis Of Water

Two-dimensional(2D)nanomaterials,such as Transition Metal Dichalcogenides(TMDCs),have attracted wide attention in the fields of electronics/photoelectronics,energy storage and conversion.Due to its special physical,chemical and biological properties,TMDCs nanomaterials show great development prospects.MoS₂ is an outstanding representative of TMDCs.It has a large surface area and strong absorption in the near infrared region,which is very similar to graphene.In addition,it is easy to functionalize the surface.These characteristics make it a promising nano-platform in biomedical applications.This thesis consists three aspects in the following parts:Firstly,we have synthesized L-cysteine-modified MoS₂ nanospheresby using a bottom-up hydrothermal method.It is assembled from 11nm nanosheets and has a particle size of approximately500nm.The addition of L-cysteine greatly improve the stability of MoS₂ in the physiological environment.Under the 808.NIR irradiation,the infrared imaging of MoS₂ in the solutioncan be observed to increase the temperature rapidly and exhibit excellent photothermal performance.Its photothermal conversion efficiency at a concentration of 50?g/m L is 34.63%.In addition,cell and hemolysis experiments confirm the safety of the material.Based on the good biocompatibility of MoS₂ and good heating effect,we perform a model treatment experiment on BALB/c mice,which achieve good tumor suppressive effects and shows less toxic side effects on normal organs and tissue.The results show that the tennis-like MoS2 synthesized in this chapter has good biocompatibility and has broad prospects in the application of nanomedicines.Secondly,water-soluble CdS QDs were synthesized by one-pot cooking at room temperature,and MoS₂@CdS nanoparticles were synthesized by hydrothermal method based on the addition of a certain amount of sodium molybdate and thiourea.The fluorescence spectrum results show that the loading of MoS₂ suppresses the recombination of pure CdS photogenerated electrons and holes,and improves the photocurrent density by enhancing their separation efficiency.The photocatalytic hydrogen production test results show that the loading of cocatalyst MoS₂ enhances the hydrogen production activity of CdS for photolysis water,further indicating that it has a good potential application in photocatalytic hydrogen production.Finally,we propose a simple syntheticalmethod of MoS₂-QDs with an average particle size of 4.2 nm.At room temperature,a certain amount of molybdenum pentachloride aqueous solution has been embellished by BSA and then almost instantaneously react with Na₂S solution in the timescale of?10–20 s.This reaction produces/yields a clear yellow MoS₂ quantum dot solution.Fluorescenc test analysis shows that the solution have strong fluorescence.The cell experiments demonstrate that the MoS₂QDs samples synthesized in this experiment had no inhibitory effect on normal cells and have good biocompatibility and broad application prospects in vivo.