Synthesis And Characterization Of Transition Metal Dichalcogenides Nanostructures

In recent years,Transition Metal Dichalcogenides?TMDs?nanomaterials showed the great application prospect in many fields,which attracts more and more attention owing to their unique chemical and physical properties.As reported,most of precursors of TMDs are toxic and labile,or contaminated,which greatly hinder the large-scale application of the material.Therefore,it is of great significance to find a non-toxic,green synthetic method.The main work of the article concentrates upon a new,nontoxic synthetic methods to prepare colloid TMDs nanomaterials of good performance,which is carried out by the following work:Firstly,the article applied the traditional heat injection method to the synthesis of TMDs nanomaterials,and prepared MoSe₂ of excellent performance by creatively adopting green non-toxic precursors of molybdenum and selenium.By the characterization of XRD,SEM,TEM,RAMAN,EDX,XPS,we known that the samples owned uniform flower-like structure with the diameter of 250 nm.The sample only had2H-MoSe₂ crystalline phase,and nanoflowers were made up by lamellar structure which had only a few molecules layer thickness.Through further electrochemical analysis,the samples had a certain activity of hydrogen evolution.The electronic structure of TMDs can be tuned by changing the composition,which is a promising method for modifying the properties of TMDs.Secondly,by changing the ratio of selenium precursors and sulfur precursors,MoS2?1–x?Se₂x nanoflowers were prepared,which overcome the stacking of traditional colloid MoS2?1–x?Se₂x.Finally,this paper studied the growth mechanism of TMDs which were little investigated.By taking aliquots during the preparation of MoSe₂ nanoflowers,we found that the colloid TMDs nanoflowers had two kinds of growth patterns: nanoparticles formed sheet firstly,then self-assembled into flowers;or the crystal nucleus owned flower petals and grew up laterally to form nanoflowers with a certain size.Additionally,by changing the amount of solvent and the temperature of injection to observe the influenceon TMDs nanomaterials synthesis,we found that the right amount of oleyamine can promote the lateral growth of TMDs,oleic acid would lead to particles into granular structure or flowers,and higher injection temperature can get wider lamellar structure.In summary,combined with the traditional heat injection method,this paper successfully synthesized nanoflowers,nanosheets,microspheres by using stable and non-toxic precursors.Such green,economic,simple,rapid method provides a important perspective of preparing various TMDs nanomaterials,thus greatly promoting the application and development of TMDs.