Preparation Of Gold-graphene Oxide And The Study Of The Effect On Nitroaromatic Compounds

Nitroaromatic compounds are a series of compounds whose-H on benzene ring is replaced by-NO2.for the-NO2 is connected to benzene ring directly,nitroaromatic compounds show the characteristic of explosity and toxicity,which is far differently from ordinary nitro-compounds,and will do great harm and threat to both humans and environment even a very little quantity of nitroaromatic compounds exists in the environment.Therefore,it's necessary to detect trace amounts of them successfully.Graphene is a kind of emerging carbon material and a kind of two-dimensional structure material which consists of an atom thick planar sheet comprising a sp2 bonded structure.There is huge superficial area existing in graphene and the huge surface will provide the reaction positions for chemical reaction which will enhance the reaction rates.All these advantage makes graphene a wildly study and application in the fields of biochemistry and sensing detection and so on.Surface enhanced Raman scattering(SERS)is a common method to detect trace substances.By surface modification of the sample,the detection of Raman active substances can be greatly enhanced.Gold,silver,palladium and other precious metals have strong Raman activity,therefor,they are commonly used in the SERS substrate to detect the measured substances.In this paper,graphene oxide(GO)was prepared by modified Hummers method using natural graphite as the raw material,meanwhile,The gold nanoparticles were prepared by hydrothermal method and seed growth method.Gold nanoparticles were modified on GO to synthesize gold-graphene oxide(Au/GO)composite materials as the Raman detection substrate.Based on this substrate,crystal violet(CV),TNT(TNT)and p-nitrophenol(PNP)were detected.The main tasks are as follows:First,the modified Hummers method was used to prepare graphene oxide.GO was obtained by ultrasonic oscillation and centrifugation.By means of TEM,XPS,UV-vis and other characterization methods,it was proved that the graphene oxide was successfully prepared by the experiment.Using sodium citrate and sodium hydroxide to reduce chlorauric acid as gold nanoparticles by hydrothermal method firstly and-two kinds of Au/GO composites were synthesized with GO doping,then CV and TNT were detected respectively with these two kinds of Au/GOs.The results show that when the CV is detected,the detection limit of both kinds of Au/GO to CV is 104mol/L;when the TNT is detected,after adding p-aminophenol(PATP),the detection limit of the two Au/GO to TNT is 10-4 mg/mL.The gold nanoparticles obtained by reduction of sodium hydroxide have a single morphology,and their detection results for CV and TNT are better.Spherical,rod and square gold nanoparticles were prepared by the seed growth method.Three kinds of Au/GO composites were obtained by ultrasonic oscillation,and PNP and TNT were detected respectively.The results showed that three different forms of Au/GO could detect the PNP of 10'5 mol/L and TNT of 104mg/mL,and the effects of different morphologic particles on the detection of the two substances were also different.