Preparation And Catalytic Performance Of Graphite Phase Carbon Nitride Catalyst

Graphitic phase carbon nitride（g-C₃N₄）has attracted much attention because of its wide raw material sources,simple preparation and suitable band gap width.However,due to its small specific surface area,the photogenic electron hole pair is easy to compound and the insufficient response to visible light.Therefore,based on modified optimization,characterization test and activity experimental investigation of g-C₃N₄,this paper overcomes the shortcomings of photogenic electron cavitation,inadequate visible light response and low specific surface area,improves the photocatalytic performance of g-C₃N₄,and completes the following work:A biochar doped graphite phase carbon nitride（KF-CN）catalyst was prepared by one-step pyrolysis with dicyandiamide as the precursor and kappa fiber as the modified material.The structure,morphology and optical properties of KF-CN were characterized by XRD,UV-Vis DRS,FT-IR,TEM,XPS,N₂ adsorption-desorption and PL.Meanwhile,the degradation rate constant of KF-CN to phenol was obviously higher than that of ordinary g-C₃N₄ under the condition of high pressure sodium lamp simulating visible light.The reactive substances in the degradation reaction were investigated by trapping agent experiment and the reaction mechanism was discussed.Urea,hydrogen peroxide,1-butyl-3-methylimidazolium bromide ionic liquid and phosphotungstate as the materials,the hydrothermal modification of g-C₃N₄ was firstly introduced into hydroxyl group by hydrogen peroxide,and then the polyhydroxy catalyst[Bmim]was prepared by in situ precipitation method.The addition of hybrid materials and hydroxyl groups is conducive to improving the hydrophilicity of the catalyst,which makes the catalyst overcome the problem of interfacial mass transfer in the water-oil reaction system and improves the performance of the catalyst.Under the condition of high pressure sodium lamp simulating visible light,using hydrogen peroxide as oxidant,the conversion rate of DBT（dibenzothiophene）in the simulated oil product reached 91%,through the circulation experiment,the catalyst has good stability,and the reaction mechanism was further discussed.