Preparation And Photocatalysis Of Sulfur Quantum Dots And Layered Sulfur Nanomaterials

Since the appearance of graphene nanomaterials in 2004,people have raised a research boom on two-dimensional nano materials,and black phosphorus,molybdenum disulfide and boron nitride have appeared one after another.Similar to carbon and phosphorus,sulfur can also exist in the form of elemental elements.Sulphur quantum dots show the unparalleled optical properties of carbon materials.In view of the shortcomings of carbon nanomaterials such as zero band gap,complex preparation and poor stability of black phosphorus nanomatcrials,new sulfur nanomaterials(sulfur quantum dots and layered sulfur nano materials)have been developed in this experiment.The photocatalytic properties of sulfur nanomaterials were characterized by transmission electron microscopy(TEM),UV-Vis absorption spectroscopy(UV),fluorescence spectroscopy(PL),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and Raman spectra.Study 1:Using thiourea as sulfur source,hydrogen peroxide as oxidant and polyethylene glycol 400 as stabilizer in alkaline medium,a simple hydrothermal method for the synthesis of sulfur quantum dots was established.The synthesized sulfur quantum dots have better dispersion in aqueous solution and stronger fluorescence intensity.The synthesized sulfur quantum dots show the fluorescence emission characteristics of excitation dependence,and exhibit good photodegradation catalytic performance and good stability,and can be reused as catalysts.Electrochemiluminescence properties of synthesized sulfur quantum dots were investigated.Electrochemiluminescence can be generated in different media(acid,alkaline,neutral).The sulfur quantum dots prepared by this method solve the problem of long preparation preparation time of traditional methods,broaden the application field of sulfur quantum dots,and provide a reference for potential photocatalytic applications of sulfur quantum dots.In view of the research inspiration of graphene,in the second study,the novel two-dimensional layered sulfur nanomaterials(S-NSS)were obtained by ultrasonic stripping method in ultra-pure water using raised sulfur powder and bovine serum protein(BSA)as raw materials.The prepared layered sulfur nanomaterials have good dispersibility and exhibit a wide range of light absorption characteristics from UV to visible region and unique multi-band photoluminescence(PL)properties.The layered sulfur exhibits obvious electrochemiluminescence(ECL)radiation phenomenon when applied to linear potential scanning or pulse step scanning.The prepared layered sulfur nanomaterials show n-type semiconductor properties,and have good air stability(stable in air for nearly 2 months).They show good visible light catalytic activity in the field of photoelectric catalysis,and can degrade Rhodamine B organic matter.The new two-dimensional nanomaterial layered sulfur prepared may be applied to the fields of photocatalysis,sensors,optoelectronics and transistors,providing a reference for the development of new materials to solve the limitations of the existing two-dimensional materials.In this paper,sulfur nanomaterials(sulfur quantum dots and layered sulfur nanomaterials)were prepared under mild conditions,simple operation,good water solubility,excellent optical stability and catalytic performance.It is expected to be used in bioluminescent marker analysis,catalytic degradation,photoelectric devices and other fields.