Study On The Liquid-phase Synthesis And The Electrocatalytic Hydrogen-evolution Properties Of Molybdenum Diselenide Nanomaterials

MoSe2 in layered transition metal dichalcogenides(LTMDs)is widely used in solid lubricating,adsorption,photocatalysis,photo luminescence,field effect transistors,photodetectors,solar cells,lithium/sodium ion batteries and electrocatalytic hydrogen evolution and other fields.MoSe2,as a promising electrocatalytic hydrogen evolution catalyst,its electrocatalytic hydrogen evolution properties can be effectively enhanced by synergistic and synchronous optimization of three types of optimization ideas,i.e.,enhance the number and activity of the exposed active sites,enhance conductivity and increase the interface contact between the catalyst and the electrolyte.In this thesis,MoSe2 nanomaterials with controllable morphology and structure were synthesized by using liquid phase method.The effects of experimental parameters at different stages on their morphology and structure were studied.And their Brunauer-Emmett-Teller properties,hydrophilicity,thermal stability and electrocatalytic hydrogen evolution performance were characterized.The main results are as follows:(1)Three typical MoSe2 nano materials were synthesized by changing the volume ratio of oleylamine and oleic acid in the organic solvent.Samples 1 was MoSe2 nanosheets with sparse and disorderly distributed fold wrinkles;Sample 2 was MoSe2 nanosheets with dense and relatively ordered distribution fold wrinkles;Sample 3 was MoSe2 nano flowers with a size of 100-200 nm.The morphology and structure of three typical MoSe2 nanomaterials are affected by the ratio of organic solvent,holding time of selenium source,injection rate of selenium source,selenium temperature,selenium holding time,ripening temperature,ripening holding time and glacial acetic acid treatment.(2)The Brunauer-Emmett-Teller properties show that the nitrogen adsorption and desorption isotherms of three typical MoSe2 nanomaterials belong to the type III isotherms and H3 type hysteresis loops.Among them,Sample 1 may has the largest combination of "ink bottle" holes,Sample 2 has the largest specific surface area and total pore volume,and Sample 3 has the largest pore size ratio and average pore size.The hydrophilicity of three typical MoSe2 nanomaterials were all improved after acetic acid treatments,and the hydrophilicity of Sample 3 was always the best before and after acetic acid treatment.Meanwhile,the acetic acid treatment can avoid the change of morphology and structure for the samples caused by the thermal treatment.The electrocatalytic hydrogen evolution performance of Sample 2 and Sample 3 are similar and better than Sample 1,which was closely related to the morphology,structure and intrinsic properties of three typical MoSe2 nanomaterials.