The Fabrication And Sensing Applications Of Noble Metal Functionalized MoS₂ Nanocomposites

MoS₂ is an important member of transition metal chalcogenides,with features of a large specific surface area,good thermal stability,and easy functionalization,which has been extensively used in the fields of catalysis,sensing and electronic devices.Noble metal nanoparticles have many advantages,such as unique optical properties,superior electronic conductivity and good biocompatibility,which have broad application prospects in the fields of new energy,electrocatalysis and biosensing.With the continuous requirement of the nanomaterials performance,the development of new nanocomposites has become one of the current research hotspot.In this dissertation,the noble metal functionalized molybdenum disulfide nanocomposites were synthesized.Moreover,their electrocatalytic activity and surface enhanced Raman characteristics were studied.On the basis of above results,electrochemical and surface-enhanced Raman sensors were constructed for the detection of chemical or biological molecules.The research content of this thesis is mainly divided into the following two aspects:（1）Core-shell gold platinum alloy functionalized molybdenum disulfide（MoS₂-Au@Pt）nanocomposites were synthesized by seed growth method.The nanocomposite modified electrode exhibited excellent electrocatalytic activity for glucose oxidation due to the synergistic effect of the core-shell gold-platinum alloy and MoS₂ nanosheet.On the basis of above results,an electrochemical sensor had been constructed for enzyme-free detection of glucose based on MoS₂-Au@Pt nanocomposite.This electrochemical biosensor showed a wide linear response over a glucose concentration ranging from 10μM to 3 mM with a detection limit of 1.08μM（S/N=3）.In addition,this electrochemical biosensor also had excellent selectivity and stability,which could be used for glucose detection in real samples.（2）Gold nanostar functionalized molybdenum disulfide（MoS₂-AuNSs）nanocomposites were prepared by seed growth method.Firstly,seed solution was prepared by decoating gold nanoparticles on the surface of MoS₂ nanosheet.Then,MoS₂-AuNSs nanocomposites with different numbers dendrites and sizes were obtained by adjusting the reaction conditions,such as surfactants,silver nitrate,and chloroauric acid.We used 4-MBA as the Raman signal molecule and a catalytic reduction model based on 4-nitrophenol to investigate the Raman enhancement effect and catalytic performance of the MoS₂-AuNSs nanocomposites,respectively.The experimental results showed that the best Raman enhancement performance of the MoS₂-AuNSs nanocomposites was prepared by using[Au³⁺]/[Au⁰]=13 and[Ag⁺]=40μM.This MoS₂-AuNSs nanocomposites was served as SERS substrates to detect penicillin and chloramphenicol.In addition,such nanocomposite also exhibited excellent catalytic activity toward reduction of 4-nitrophenol.