Synthesis And Catalytic Activity Of G-C₃N₄ And Imine Compound Composites

The g-C₃N₄ is mainly a covalent solid polymer consisting of two elements,C and H,consisting essentially of a s-triazine ring and a few residual amino groups.The material can be synthesized by polymerizing various nitrogen-rich substances such as melamine,dicyandiamide,cyanamide,urea and thiourea.Such catalysts have the characteristics of visible light response,suitable forbidden band width,high chemical stability,thermal stability,and easy structure modification,etc.,Hydrogen production from photolysis of visible light,photocatalytic reduction of CO₂,and photocatalytic degradation of organic pollutants.The selective organic synthesis and other aspects show a good application prospect and high research value.However,because g-C₃N₄ has a small specific surface area,a narrow visible light response range,a high photoelectron-hole pair recombination rate,and a low light quantum efficiency,it has a low photocatalytic activity,which greatly limits its application.Therefore,the research on modification of g-C₃N₄ by means of nanostructure design,exfoliation,doping,copolymerization and other means has not diminished in recent years.In this paper,based on the shortcomings of low photocatalytic efficiency of g-C₃N₄,bulk bulk g-C₃N₄synthesized from melamine precursor is treated with concentrated sulfuric acid to achieve pyrolytic stripping of g-C₃N₄,and the resulting solid is at a high temperature.Thermal polymerization was again conducted to obtain more disperse g-C₃N₄.Through the heat treatment of the acid,the regular network stack structure of g-C₃N₄ itself is destroyed,and the process of re-thermal polycondensation further exacerbates the irregularity of g-C₃N₄,resulting in structural defects of g-C₃N₄,and the existence of defects can be solved.Effective inhibition of photoelectron-hole recombination increases photocatalytic activity.At the same time,the structural changes were studied by powder X-ray diffraction,infrared spectroscopy,thermogravimetric analysis,fluorescence spectroscopy,ultraviolet absorption spectroscopy,and transmission electron microscopy.At the same time,photocatalytic degradation of rhodamine B was used to evaluate its catalytic activity.The naphthalimide structure has a large?-conjugated structure,good thermal stability and light stability.In this paper,the 4-nitro-N-(p-carboxyphenyl)-1,8-Naphthalimide(HL)compound with a naphthalimide structure which has a large?-complex was first designed and synthesized.By doping and blending g-C₃N₄ with a compound HL having a naphthalimide structure to change the electronic properties of the conjugated compound.The organic compound of the yoke structure and g-C₃N₄ form a heterojunction under high temperature conditions,and the contact interface improves the electron transfer and transfer between the two,thereby increasing the photocatalytic activity of the rhodamine B of the g-C₃N₄ complex.Compared to pure g-C₃N₄,g-C₃N₄after complex HL can degrade rhodamine B faster.The structure of HL/g-C₃N₄ complex and the photocatalytic degradation of rhodamine B were characterized by powder X-ray diffraction,fluorescence spectroscopy,UV-visible absorption spectroscopy,infrared spectroscopy,nuclear magnetic resonance spectroscopy and impedance spectroscopy.