Research On Structural Regulation Based On G-C₃N₄ Photocatalyst

The increasingly industrialized process has made people’s lives more fulfilling,and the environmental pollution that comes with them has become more and more serious.Especially the water pollution problems closely related to human life need to be paid enough attention.Photocatalytic technology can convert solar energy into chemical energy without secondary pollution.In recent years,it has been widely used in the treatment of organic pollutants in wastewater.However,due to the narrow visible light response range of photocatalysts,the specific surface area is small,resulting in fewer active sites,which limits the application of photocatalytic technology in water treatment.In this paper,a new type of organic polymer semiconductor graphite phase carbonitride（g-C₃N₄）was studied,and its surface structure was adjusted by soft template method to enhance its photocatalytic performance.Secondly,we combined g-C₃N₄ and chitosan（CS）via the blend crosslinking method to prepare easily recoverable bead particles,which provides a possibility for practical industrial application of g-C3N4.In this paper,melamine was used as the precursor,and polymethyl methacrylate（PMMA）and polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer（P123）were used as soft template to prepare g-C₃N₄ material using a facile two-step synthesis method.A series of characterizations such as SEM,XRD,FT-IR,DRS,BET,XPS were carried out to investigate structural properties.The photocatalytic degradation was based on Rhodamine B（Rh B）as the target pollutant.The results show that the soft template method can generate more pore structure and increase the specific surface area which can provide more active sites and enhance photocatalytic oxidation ability.The degradation rate of Rh B can reach 92%under visible light for 120 min with PMMA as soft templating agent.g-C₃N₄ prepared with P123 as soft templating agent showed higher oxidizing ability where the degradation rate of Rh B can reach 98.7%under visible light for 40 min.In addition,the reducing ability was also significantly improved.The amount of H₂ produced by visible light for 1 h can reach 1074.9μmol?g^-1.After repeated use for 4 times,the catalytic performance of the catalyst did not decrease significantly and had good stability.In this paper,a series of g-C₃N₄-CS beads were synthesized using mixed cross-linking of g-C₃N₄ prepared by high temperature calcination of melamine and CS,and a series of optical and electrical characterization,photocatalytic activity and stability were investigated.The results show that the prepared g-C₃N₄-CS beads have high degradation performance and stability due to the synergistic effect of in situ adsorption and photocatalytic degradation.In addition,the g-C₃N₄-CS beads can be regenerated by a simple alkaline solution,and the regenerated g-C₃N₄-CS beads exhibit excellent stability after four repeated tests with a mass loss of less than 10%.