Preparation Of G-C₃N₄ Composite Photocatalyst And Its Photocatalytic Activity For Degradation Of Organic Pollutants

With the increasingly serious environmental pollution problems,sewage treatment has become a hot issue of concern in the world today.Green environmental photocatalysis technology has the advantages of simple operation,low cost and direct use of sunlight,and has become the first choice for environmentally friendly sewage treatment technology.Therefore,the development of ideal semiconductor materials has broad prospects for the application of photocatalytic technology.Graphite phase carbonitride ?g-C₃N₄? is a non-metallic semiconductor material with a suitable band gap ?2.7 eV?.Due to its obvious response to light,low cost,simple preparation process and good chemical stability.It has become an ideal semiconductor material for photocatalytic technology.However,the shortcomings of fast recombination of electron-hole pairs,small specific surface area,low visible light utilization and difficulty in recycling limit the practical application of g-C₃N₄.Therefore,according to the merits and demerits of g-C₃N₄,the composite photocatalysts of Fe₃O₄/g-C₃N₄/RGO and g-C₃N₄/ATP/Bi₂WO₆ were constructed to improve the photocatalytic activity of g-C₃N₄.The specific contents of this paper are as follows:?1?Fe₃O₄/g-C₃N₄/RGO composite photocatalyst was prepared by hydrothermal method.Fe₃O₄ can improve the magnetism of the composite catalyst and acts as the storage of electrons.It can provide more active sites to react adequately with pollutants.The addition of reduced graphene oxide ?RGO? effectively inhibits the recombination of electron-hole pairs in g-C₃N₄ and transfers electrons to Fe₃O₄ rapidly,extending the lifetime of electron-hole pairs of g-C₃N₄ and improving the composite of high electron-hole pairs of g-C₃N₄ itself.Thus he photocatalytic activity of g-C₃N₄ is enhanced.The photocatalytic properties of Fe₃O₄/g-C₃N₄/RGO composite photocatalyst were tested by XRD,Raman,TEM,FT-IR,UV-vis and photocurrent impedance measurements.The results show that the prepared composite photocatalyst not only has good crystallinity and morphology,but also has a remarkable improvement in the ability to degrade tetracycline compared with the monomer g-C₃N₄.?2?A novel composite photocatalyst modified by Bi₂WO₆ quantum dots ?QDs? on the surface of g-C₃N₄ intercalation structure constructed by Attapulgite ?ATP? that is successfully fabricated via high temperature calcination and in-situ method.Under the irradiation of visible light,the Z-system composite photocatalyst g-C₃N₄/ATP/Bi₂WO₆ shows excellent photocatalytic degradation ability for removing 2-mercaptobenzothiazole ?MBT?.The enhanced photocatalytic activity compared with pure g-C₃N₄ is enhanced,on the one hand,Bi₂WO₆ QDs uniformly dispersed on the material can expose more active sites.On the other hand,introducing the intercalation structure of ATP nanorods structure accelerated the transport of electrons between g-C₃N₄ and Bi₂WO₆ quantum dots that enhanced the photocatalytic activity of g-C₃N₄/ATP/Bi₂WO₆ photocatalyst.Therefore,the g-C₃N₄-based photocatalyst produces more active substances for wastewater treatment.