Construction And Application Of Functionalized Graphene Or Sulfide Molybdenum Nanocomposite Electrochemical Sensors

With the rapid development of the times,a large number of chemical enterprises have been established,and bring great pressure to the environment while bringing benefits to mankind.A large amount of industrial wastewater discharged into rivers and lakes and the soil,causing pollution to the soil and water environment,and the most toxic substances in the environment is very difficult to degrade toxic substances accumulate will accumulate through the food chain into the human body,resulting in various diseases to humans.Although we all know that there are great risks to living environment,we lack a simple,fast and accurate method to detect environmental pollutants.At present,many methods for detection of environmental pollutants,such as gas chromatography,liquid chromatography and other methods,but the cost is high,is not easy to carry,not large-scale applications,and electrochemical method has the advantages of low cost,fast and convenient,wide concentration range of sensitivity and high accuracy,the advantages of detection,detection can be widely used in the environment pollutant.In electrochemical analysis,the electron transfer rate and the sensitivity of the electrode are increased by synthesizing a composite of nanomaterials onto the surface of the electrode.In this paper,three kinds of modified electrode based on layered nanomaterials were constructed to measure environmental pollutants.The main research contents are as follows:1.Ionic liquid functionalized graphene oxide-Au nanoparticles assembly for fabrication of electrochemical 2,4-dichlorophenol sensorSelf-assembly of graphene oxide?GO?and Au nanoparticles?AuNPs?was covalently modified by ionic liquid?IL?containing amino groups to prepare the ternary nanocomposite of IL-GO-AuNPs.UV,IR spectra,X-ray power diffraction and scanning electron microscope confirmed the uccessful hybridization of these three components,leading to the larger surface area and better dispersity.Then a sensitive2,4-Dichlorophenol?2,4-DCP?sensorwasestablishedbasedon IL-GO-AuNPs modified glassy carbon electrode.The IL-GO-AuNPs composite gave rise to a desirable access to the electron transfer and electrocatalytic capacity toward the oxidation of 2,4-DCP.Differential pulse voltammetry was employed for the quantitative analysis of 2,4-DCP.The proposed sensor showed a wide linear range from 0.01 to 5?M with a low detection limit of 3nM?S/N=3?.The developed sensor was successfully used for the determination of 2,4-DCP in water samples with satisfactory recoveries and stability.The excellent electrocatalytic performance could be attributed to the high conductivity and more active sites of IL-GO-AuNPs.2.Simultaneous determination of copper?II?and antimony?III?by ionic liquid functionalized graphene oxide modified carbon paste electrodeIn this experiment,the carbon paste electrode was modified by the ionic liquid functionalized graphene?IL-GO?as the working electrode to detect copper and antimony.The ionic liquid is ring-opened on the surface of the graphene oxide by covalent modification to improve its electrical conductivity.By scanning electron microscopy?SEM?and infrared?IR?spectra,it can be seen that the ionic liquid was successfully modified to the surface of the graphene oxide.By direct electrochemical characterization can be seen through the ionic liquid functionalized graphene its conductivity was significantly enhanced and can be used as an electrode modifier to detect copper and antimony.Finally,under optimal experimental conditions?Deposition time 50s,Deposition electric potential-0.3V,0.3M HCl bottom liquid?detected with differential pulse voltammetry.In the linear concentration range,the detection limit of calculated Cu???and Sb???calculated as 4.0×10^-8M and6.0×10^-8M.3.Determination of 2-naphthol by molybdenum disulfide nanomaterial with sheet structure modified glassy carbon electrodeA molybdenum disulfide?e-MoS₂?nanomaterial with sheet structure was synthesized by hydrothermal method.The glassy carbon electrode was modified with this nanomaterial and an electrochemical sensor e-MoS₂/GCE was prepared to detect2-naphthol.Though the SEM and XRD spectrum,the molybdenum disulfide?MoS₂?nanomaterial with sheet structure can be proved successful synthesis and has larger surface area.The electrons produced by the oxidation of 2-naphthol can be transferred by the electrochemical sensor.Through the electrochemical characterization,the molybdenum disulfide?MoS₂?nanomaterial with sheet structure can be seen compared to the commercial molybdenum disulfide MoS₂ has better electron transfer rate and more active sites.By using differential pulse voltammetry?DPV?for the quantitative analysis of 2-naphthol,this sensor has a wide linear range?0.02 M⁵0 M?and low detection limit?6.7nM?.In addition,the electrochemical sensors based on molybdenum disulfide?MoS₂?nanomaterial with sheet structure modified glassy carbon electrode have good stability and reproducibility as well as strong anti-interference ability.