Design And Study Of Photoelectric Properties Of Two Dimensional Sulfide Semiconductor Nano Structural Materials

In recent years,the problem of atmospheric particulate pollutions has become more and more serious,causing great harm to human health.Heavy metal ions and polycyclic aromatic hydrocarbons?PAHs?in atmospheric particulate pollutants are highly susceptible to cause human diseases and cancer.Therefore,it is urgent to develop efficient and rapid methods for detection of heavy metal ions and PAHs.With the depth study of nanomaterials,two-dimensional sulfide semiconductor nanomaterials with unique optical and photoelectrochemical properties have been widely used in the analysis and detection of environmental pollutants.Among them,The photoelectrochemical?PEC?uses visible light as the excitation source and photocurrent as the detection signal.The PEC sensor has been widely applied to biological,pharmaceutical and environmental pollutants detection,because it has the advantages of low background signal,fast response and high sensitivity.In this paper,we have studied two-dimensional sulfide semiconductor nanomaterials in depth.In addition,we successfully developed novel quantum dots fluorescent probe and PEC sensor for high sensitive detection of heavy metal ions Fe³⁺and PAHs pollution benzo[a]pyrene?BaP?,respectively.1.Enhanced hydrothermal synthesis of MoS₂ QDs for highly efficient fluorescent detection of Fe³⁺In this paper,a facile and enhanced hydrothermal method was applied to prepare molybdenum disulfide quantum dots?MoS₂ QDs?.The as-prepared MoS₂ QDs are small and uniform in size distribution characterized by HRTEM,meanwhile exhibites excellent photoluminescence properties and water-dispersibility.On account of electrostatic interaction and induced aggregation in the presence of Fe³⁺.Fe³⁺could induced the photoexcited electron transfer and the aggregation of MoS₂ QDs,which lead to the fluorescence quenching of MoS₂ QDs.Based on the above,a new quantum dots fluorescent probe was constructed to detect Fe³⁺.The fluorescence quenching rate was related to Fe³⁺concentration in the range from 5 to 250?mol·L^-1 with a detection limit of 1.66?mol·L^-1.And the fluorescence quenching rate was related to the logarithm of Fe³⁺concentration in the range from 250 to 600?mol·L^-1.The results of Fe³⁺detection in actual tap water samples showed that the constructed MoS₂ QDs fluorescent probe has a good mean recoveries?95.1-100.6%?and RSD?0.05-0.14%?.Which meets the the maximum level of Fe³⁺0.3 mg·L^-1(⁵.4?mol·L^-1)in drinking water set by the World Health Organization?WHO?.2.Construction of a photoelectrochemical sensor composed of few-layered WS₂ NSs and?-CD-MoS₂ QDs composites for the ultrasensitive detection of BaPA n-butyl lithium intercalation stripping method was applied to prepare tungsten disulfide nanosheets?WS₂ NSs?.Then,WS₂ NSs and?-cyclodextrin??-CD?modified?-CD-MoS₂ QDs are compounded by hydrogen bonding between amino group and hydroxyl group.After assembling on the ITO electrode,the energy level matching and synergistic photoelectric effect between?-CD-MoS₂ QDs and WS₂ NSs reduce the combination of photogenerated electrons and holes,an enhanced photocurrent signal was observed.In the presence of BaP,because of the host-guest interaction between?-CD and BaP,BaP could bind to?-CD-MoS₂ QDs in the nano-composites,which hinders the electron migration to the ITO electrode and weakens the photocurrent signal.Thus the trace detection of BaP has been realized.And the rate of photocurrent change was related to BaP concentration in the range from 1 to 20 nmol·L^-1 with a detection limit of 0.33 nmol·L^-1.Then,a novel high sensitive and high selective PEC sensor for detection of polycyclic aromatic hydrocarbon pollutants BaP has been successfully constructed.Figure[37]table[7]reference[155]...