Preparation And Application Of Porous G-C3N4-based Photocatalytic Materials

As a green and efficient advanced oxidation technology,photocatalysis uses cheap solar energy to drive the photocatalytic process.Nowadays,there are many types of photocatalytic materials.g-C3N4 materials are promising photocatalytic materials in recent years because of their stable physical and chemical properties and easy availability from raw materials.However,the photocatalytic activity of bulk g-C3N4 materials is not well used for various photocatalytic reactions.Porous g-C3N4(PN)is a promising g-C3N4 material.On the basis of PN,this article optimizes PN materials by means of heterojunction modification and ion modification,in order to solve the shortcomings of PN materials and then use them for practical applications.The main research are as follows:In chapter 2,we prepared K+modified porous g-C3N4 material(KPN)by embedding K+in the framework of PN using an ion modification strategy.The photocatalyst KPN2 with the optimal amount of K+was finally prepared by adjusting the activity of KPN by changing the amount of K+ modification.Morphology and chemical structure characterization show that the porous structure leads to KPN having a larger specific surface area.The photoelectric performance characterization shows that KPN has obtained better visible light absorption capacity and higher photo-generated carrier separation efficiency on the basis of PN.KPN was applied to the photocatalytic degradation of two different antibiotics.It was found that the photocatalyst had better photocatalytic degradation activity and better cycle stability under visible light driving.It was also found that it could better adapt to the photocatalytic degradation of antibiotic wastewater with different concentrations.Finally,a possible photocatalytic degradation mechanism was proposed based on the photoelectric properties of the material and the active species detected.In chapter 3,we prepared V2O5 and F+co-modified porous g-C3N4 photocatalyst(VFPN)by a two-step strategy.Morphological and chemical structural characterizations show that VFPN has a larger specific surface area due to the porous structure.Photoelectric characterization shows that VFPN has better visible light absorption capacity and higher photo-generated carrier separation efficiency based on PN.VFPN was applied to the photocatalytic degradation of organic dyes.It was found that the photocatalyst had better photocatalytic degradation activity and better cycle stability under visible light driving.Finally,a possible photocatalytic degradation mechanism was proposed based on the photoelectric properties of the material and active species capture experiments.In chapter 4,we prepared BiOBr-modified porous g-C3N4 photocatalyst(BPN)by a two-step method.The morphological and chemical structural characterizations show that the porous structure leads to a larger specific surface area of BPN.The photoelectric performance characterization shows that BPN obtains better visible light absorption capacity and higher photocarrier separation efficiency on the basis of PN.BPN was applied to the photocatalytic degradation of antibiotics and organic dyes.It was found that the photocatalyst had better photocatalytic degradation activity and better cycle stability under visible light driving.At the same time,it was found that the photocatalyst could better adapt to the photo catalysis of antibiotic wastewater with different concentrations.Finally,a possible photocatalytic degradation mechanism was proposed based on the photoelectric properties of the material and the active species detected.