Synthesis And Properties Of Transition Metal Dichalcogenide Nanosheets

Two-dimensional transition metal chalcogenide?TMDs?nanomaterials have received wide attention in the energy and detection fields because of their unique properties.On one hand,TMDs,as a substitute for conventional electrocatalyst metal platinum,have brought great hopes for reducing costs in the field of electrochemical hydrogen evolution?HER?.The study of TMDs as electrocatalysts has acquired rapid progress in recent years.Increasing the catalytic activity of electrocatalysts is an important issue that needs to be solved urgently.On the other hand,the application of TMDs in the field of photodetectors is becoming more widespread.It is the hopes and goals of researchers to build high-performance photodetectors.This article mainly studied the characteristics of TMDs nanomaterials in the fields of electrocatalytic hydrogen evolution and photodetector respectively.The main scientific research results are as follows:?1?Arrays of ZnSe/MoSe₂ nanotubes on fluorine-doped tin oxide?FTO?glass substrates are synthesized and employed as a high efficient binder-free HER electrocatalyst for the first time.Compared with the bare MoSe₂ elelctrocatalyst,the hybrid ZnSe/MoSe₂ nanotube electrocatalyst illustrates striking kinetic metrics with a small Tafel slope?73 mV per decade?and a low onset potential?68 mV?.Beside benefits from the nanoarray structure as binder-free electrode as well as interlayer expansion of layered MoSe₂,electron transfer from n-type ZnSe to MoSe₂ induced by alignment of energy levels at heterointerface contributes to fast electron transport and active electrocatalytic behavior of MoSe₂ at the electrocatalyst-electrolyte interface,which is responsible for the significant improvement in HER performance.This work opens up a new way for the development of high performance HER electrocatalysts by designing semiconductor heterojunctions.?2?The research of photodetector based on solution-processed two-dimensional material WS₂ nanosheets with high sensitivity and high response speed.The prepared WS₂ nanosheets with the characteristics of layer stacking enhance the absorption of light due to its unique synthesis method.Subsequently,we construct the multilayer WS₂-based two dimensions-three dimensions?2D-3D?compatible device.Under the light illumination,this photodetector shows high performance with a high detectivity of²×10¹² Jones(Jones=cm·Hz^1/2W^-1),a fast response speed of about up to1.973/7.236?s,and with an ultrahigh external quantum efficiency?EQE?of 293.6%in the condition of optical power density of 1.55?W cm^-2,which is better than most of the WS₂-based photodetectors reported thus far.The simple device preparation process and material preparation method would provide a broad prospect for the application of high-performance photodetectors.