Preparation And Application Of Environmental Analysis Of Graphene Composite Materials

As a new type of carbon nano-material, graphene has manyexcellent properties, such as the high speed of electrontransmission, large specific surface area, good thermalconductivity good thermal conductivity, etc. Hopefully, graphenewould be widely used in the field of electrochemical detection andcatalysis. Electrochemical sensor, as a new kind of checking tool,has advantages of simple preparation, fast response speed, highsensitivity and low cost, etc. Electrochemical sensors are widelyused in the field of food safety, clinical diagnosis and environmentalmonitoring, etc. The nanometer sized material has the excellentproperties, which is different from the normal materials in theaspects of magnet, light, heat, electric and mechanical. Andnano-material is applied in the preparation of sensors and it cangreatly enhance the property of sensors. On the basis of graphene,this thesis studies the application of graphene-basednanocomposites in electrochemical sensors. The main contentsinclude the following three parts:1. To introduce the harm and detection methods of nitrophenol inorganic compounds; the preparation, classification, characterization methods and applications of chemical modifiedelectrode; the properties and preparation of graphene andgraphene composites, etc.2. To synthesize the graphene oxide (GO) through the typicalmethod of hummers, using cation exchanger-Nafion to dispersethe GO, taking the method of dispensing to dispense the GOdispersion on the surface of glassy carbon electrode, and theGO/Nafion/GCE electrochemical sensor is prepared. And then, thenickel nanometer particles is deposited on the GO/Nafion/GCEmodified electrode surface by the function of electrochemicalreduction and the Ni/Nafion/rGO/GCE new type of nano particlessensor is prepared, and electrochemistry and SEM are employedto characterize it. Finally, the characteristics of the modifiedelectrodes and the electrochemical behavior of p-nitrophenol onthe modified electrodes are studied by cyclic voltammetry (CV).3. P-nitrophenol has three kinds of isomers, and because of thesimilarity of their structures and properties, the simultaneousdetermination is relatively difficult. Traditional testing methodshave some problems, such as expensive instruments,complicated pretreatment and inappropriate on-site examination,etc. This article uses the Ni/Nafion/rGO/GCE sensor to achievesimultaneous determination of nitro phenol, o-nitrophenol andp-nitrophenol. And there is a detailed research on it by themethod of cyclic voltammetry (CV) and linear sweep voltammetry(LSV). The result shows that the composite modified electrodeshows good electro-catalytsis ability on the nitro phenol,o-nitrophenol and p-nitrophenol, and the electrochemical response of electrode on nitro phenol, o-nitrophenol andp-nitrophenol is also effectively enhanced. In the optimalexperimental condition, this sensor can achieve the sensitive andsimple detection of nitro phenol, o-nitrophenol and p-nitrophenol,and it also has a lower limit of detection and good stability, and itcan be used for sensitive detection of actual study samples.