Construction And Properties Of Graphite Phase Carbon Nitride Based Photocatalytic System

In recent years,with the rapid development of textile and food industry,a large number of dye wastewater is discharged into the environment,which seriously affects the ecological balance and human health.Photocatalytic technology has attracted wide attention due to its advantage of using clean solar energy as the driving force,and graphite-phase carbon nitride（g-C₃N₄）has been considered as one of the most promising photocatalytic materials.However,for single component g-C₃N₄,its photocatalytic activity still suffers from the problems of low visible light utilization and high charge carrier recombination rate,which limits its further application.Therefore,two g-C₃N₄-based composite photocatalysts were designed and prepared in this paper,and showed high-efficiency degradation performance of azo dye amaranth.The detailed research contents are listed as follows:（1）The Z-scheme heterostructure system composed of three-dimensional flower-like Fe₂O₃ and two-dimensional sheet-like g-C₃N₄ was constructed by a simple solvothermal method.The introduction of Fe₂O₃ not only enhances the absorption of visible light,but also strengthens its conductivity that improves transport performance of charge carriers.Meanwhile,the formation of heterostructure between Fe₂O₃ and g-C₃N₄ also promotes the efficient separation and transfer of photo-generated electrons and holes.By optimizing the experimental conditions of such as H₂O₂ dosage,Fe₂O₃ loaded amount and pH value,8 wt%Fe₂O₃/g-C₃N₄exhibited excellent photocatalytic degradation activity of amaranth that the degradation efficiency could reach 97.6%within 10 min.（2）Ag₃PO₄ nanoparticles were coupled to g-C₃N₄ nanotubes（G-C₃N₄）by in-situ deposition method,in which not only Ag₃PO₄ can enhance the absorption of visible light and the electrical conductivity of the composite system,but also some Ag₃PO₄ can be further corroded by the photons to form Ag nanoparticles that are used as the charge transport channel.Thus,the utilization efficiency of charge carriers has been greatly improved.By optimizing Ag₃PO₄ loaded amount,15%Ag₃PO₄/G-C₃N₄ could achieve the degradation efficiency of 95%within 20 min.