Electrochemical Preparation Of Graphene/TiO₂ Composites And Degradation Of 3,5-dinitrosalicylic Acid In Anoxic System

A stable dispersion in mixed solvent of water and N,N-dimethyl formamide?DMF?of graphene was synthesized by one-step electrochemical approach.Here we demonstrate about electrochemical stripping graphite to prepare graphene influence by different electrolytes.The physical and chemical properties of the stripping product had been characterized by using X-ray diffraction?XRD?,X-ray photoelectron spectroscopy?XPS?,Fourier transform infrared spectroscopy?FTIR?,UV-Vis spectrophotometer?UV-Vis?,Scanning electron microscopy?SEM?,Transmission Electron Microscope?TEM?.The characteristic results of XRD showed that it could improve the efficiency of graphite stripping when H₂SO₄ was used as electrolyte mother liquid and amount of HNO₃ was doped in electrolyte;XPS and FTIR results indicate that the electrochemical stripping products preserve the intrinsic structure of graphene,distance between layer is enlarged,layer have high transmittance and less reactive groups are generated on six carbon ring and the conjugated?bond structure of G get good maintain.The results of SEM and TEM shown that the surface morphology of the as-prepared graphene was folded lamellar structure and have good transparency;its thickness varies from 0.8 nm to a few nanometers.The G/nano TiO₂ photocatalytic composites were prepared by the method of sol-gel and high temperature heating under nitrogen protection using butyl titanate ester and G as precursors.The structural properties and microcosmic morphology of the graphite stripping product had been characterized by using XRD?FTIR?Ultraviolet–visible spectroscopy?XPS?SEM and TEM technologies.The photocatalytic properties in the anoxic water of different G/TiO₂ composites dosages were studied by using 3,5-Dinitrosalicylic acid?DNS?as probe and ultraviolet light as light source.The results show the as-prepared G/TiO₂ microcosmic morphology showed that well crystallized,closely combined with the TiO₂ was found to be deposited on G.The degradation experiment showed that G/TiO₂ composites have good performance for the photocatalytic degradation of DNS,and photocatalytic activity has a direct influence by doping contents.Photocatalytic degradation of 3,5-Dinitrosalicylic acid has been investigated in the G/TiO₂ anoxic system under UV irradiation.The effects of various paramaters such as pH value,catalytic amount and initial concentration of 3,5-Dinitrosalicylic acid on photocatalytic degradation kinetics were studied.The qualitative and quantitative analysis for degradation intermediate products and dechlorination mechanism were studied by using HPLC?HPLC-MS and IC technologies.The results show that the weak alkaline solution was favor for the degradation of3,5-Dinitrosalicylic acid.In addition,initial concentration negatively correlated with degradation rates of 3,5-Dinitrosalicylic acid degradation.The G/TiO₂ dosage showed an indistinctively inhibitory effect on 3,5-Dinitrosalicylic acid degradation.The qualitative and quantitative analysis for degradation intermediate products indicated that the nitro groups is removed from benzene ring,the middle products of5-Aminosalicylic acid and phloroglucinol are produced from the photocatalytic reduction reaction of 3,5-Dinitrosalicylic acid under the anoxic condition,part of3,5-Dinitrosalicylic acid is decomposited and CO₂ and H₂O are generated by photocatalytic oxidation.