The Study Of Synthesis And Photocatalytic Performance Energy Storage And Transfer Of Molybdenum Disulfide Composites

In order to protect the natural environment and maintain human sustainable development,semiconductor photocatalysis has recently become a potential research topic due to its efficient removal for organic pollutants with high toxicity and degradation-resistant property from waste water.MoS₂ nanomaterials possessed many merits including the narrow band gap,wide light response range,strong adsorption and plentiful exposured edge sites,large surface area and adjustable band from 1.19to 1.9eV resulting in the absorption wavelength of light up to 1030nm.Therefore,it is very suitable for photocatalytic degradation of organic pollutants under visible light.In this study,to improve photocatalytic ability of MoS₂,we have successfully synthesized MoS₂nanocomposite catalyst including MoS₂@MOF and BiOCl/MoS₂ by solvothermal method.The resulting samples were characterized by XRD?XPS?SEM?DRS?BET?PL and FT-IR.Photocatalytic properties of the MoS₂@MOF was evaluated by degrading rhodamine B and mythylene blue solutions under visible light,and its adsorption properties was evaluated by adsorbing mythylene blue.We also studied on photocatalytic properties of BiOCl/MoS₂ and explored the photocatalytic mechanism further.The research works and results in this thesis are described as follows:?1?The MoS₂@MOF with porous layered structure was synthesized successfully by solvent hydrothermal method using Mo-MOFs and thiourea as a precursor,and Mo-MOFs was obtained by refluxing reaxtion between MoO₃ and imidazole.The MoS₂@MOF with mole ratio of 1:2 exhibited the better crystallizability and photocatalytic activity for degrading both rhodamine B and mythylene blue under visible light.?2?The as-prepared MoS₂@MOF showed the maximum adsorption capacity(453.88 mg g^-1)of MB at 35^oC for 24h.During 12 hours of adsorption process,the absorption curve fits in well with Langmuir adsorption model,and the adsorption properties remained stable in a wide range of pH values,especially in the alkaline condition.The adsorption rate increased with increasing temperature.The strong adsorption of adsorbents with large pore volume is due to the increasing collision probability between the adsorption site and the methylene blue molecule.?3?We fabricated BiOCl/MoS₂ composites with Z-scheme structure by a facile one-step solvothermal approach using ethylene glycol and alcohol as solvent.The products with Bi/Mo mole ratio of 1:2 showed the best photocatalytic performance,and the BiOCl/MoS₂ possessed an excellent degrading rate of 96.3%for rhodamine B within 21 min under visible light irradiation.Reaction rate constant was 0.1733min^-1,which is 3.4 times as much as the pure BiOCl.Radical trapping experiments indicated that·OH and h⁺were the main reactive species responsible for the degradations,further resulted in de-ethylated reaction.For artificial heterogeneous Z-scheme photocatalytic system,not only separation efficiency of photogenerated carriers can be improved through carriers transfer at the interface,but also separated electrons or holes possess higher redox ability.