Preparation And Performance Study Of Two-dimensional Nanometer Materials MoSe₂

Two-dimensional transitional metal dichalcogenides?TMDs?nanostructures are similar to grapheme,and possess unique layers structure and excellent physical and chemical properties,and show a wide application in energy storage,catalysis,friction and electron device.But because of the low conductivity and few active sites,the application of MoSe₂ in the photocatalytic field has been greatly limited.The results show that we can control the morphology of MoSe₂ and composite with MoSe₂ to improve the photocatalytic activity and expend its application range.Therefore,in this thesis,a simple and versatile hydrothermal method was used to synthesis pure MoSe₂ nanosheets,which further are doped and composited.On this basis,we also study their morphology,photocatalytic activity etc.The main content is as follows:?1?MoSe₂ nanosheets were prepared via a simple and mild hydrothermal method under high temperature and high pressure,using sodium selenite and ammonium molybdate tetrahydrate as selenium and molybdenum source,respectively,with hydrazine hydrate as reductant,deionized water as solvent.The hollow nanoflowers structured MoSe₂ can be didentified by many test methods,including XRD,EDX,SEM.Experimental results show that our sample has strong adsorption capacity,and the degradation of Rhodamine B?RhB?dye solution can reach 56.8% under 150 minutes visible light irradiation.The present work expands the application of MoSe₂ to the field of photocatalytic degradation of pollutants.?2?The solution in the preparation process of of MoSe₂ is used as MoSe₂ precursors,and a moderate urea and cobalt nitrate hexahydrate were added to it,then obtained novel Co/N codoped MoSe₂ hollow nanoflowers through heated in autoclave and annealed in a quartz tube furnace.Factors affecting concentration of dopants and reaction time were studied,the products were characterized by XRD,TEM,SEM and XPS,in addition,we studied the possible mechanism of the formation.The results demonstrate the recombination rate of electron-hole decreased,surface area and photocatalytic activity increased.?3?Under the assistance of organic solvents Ethylenediamine?EDA?,we present a facile method for the synthesis of hierarchical nanosheet-based MoSe₂ nanospheres by an anion-exchange reaction of the inorganic –organic hybrid MoO3-EDA nanorods with selenium solution.Experimental proof that the prepared nanosheet-based MoSe₂ nanospheres showing excellent photocatalytic performance under the irradiation of visible light.