Design And Synthesis Of 0D-2D MoO₃/g-C₃N₄ Photocatalytic Material And Its Degradation Performance On Tetracycline

In recent years,graphite-phase carbon nitride（g-C₃N₄）has been widely used in wastewater treatment due to its low cost,green and pollution-free advantages,but a single block g-C₃N₄ has high charge recombination rate,low specific surface area and low redox The shortcomings of potential make it limited in practical applications.In order to improve this problem,after in-depth research,it is found that exfoliating massive g-C₃N₄ to prepare two-dimensional（2D）g-C₃N₄ nanosheets can expand the specific surface area,enrich the active centers and shorten the volume diffusion length.However,the removal of pollutants by a single g-C₃N₄ nanosheet is far from meeting the requirements of photocatalytic removal of pollutants.In order to improve its degradation performance,on the one hand,a heterojunction can be constructed to achieve the purpose of increasing the electron transmission rate.Constructing a Z-scheme heterojunction not only realizes effective charge separation,but also gives the photocatalytic system a stronger redox capability than traditional heterojunctions.On the other hand,0D nanomaterials are widely used to build 0D-2D nanocomposite structures by compounding with 2D g-C₃N₄ due to their advantages such as high specific surface area,short electron transmission distance,and easy control of size and distribution.At the same time,controlling the morphology of the material can extend the total area per unit mass of the material,thereby increasing the active center.Therefore,finding a suitable photocatalyst to construct a Z-scheme system with 0D/2D g-C₃N₄ is a very promising approach.In this paper,a Z-scheme 0D/2D MoO₃/g-C₃N₄ composite photocatalyst was designed and prepared by a simple calcination method for the first time.Constructing the 0D-2D structure is conducive to forming a more effective Z-scheme heterojunction,shortening the carrier transmission distance and providing a fast transmission path.The shape and size of the material,the peak intensity information of the crystal lattice,the specific surface area and the pore structure,the photoelectric performance and the element composition were characterized and explained.The catalytic activity of the tetracycline was evaluated by the degradation effect of tetracycline.The results show that 0D-2D MoO₃/g-C₃N₄（MOCN）Z-scheme heterojunction is significantly better than the original g-C₃N₄ material.Especially under visible light irradiation（λ>420nm）,the best reference MOCN-0.5 can reach a removal rate of85.9%within 100 min,and its degradation rate constant is 2.3 times that of g-C₃N₄（CNNS）.In addition,the effect of real water substrate and sunlight on photocatalytic degradation has also been systematically studied.It is found that the wide spectral range of sunlight can provide highly responsive ultraviolet and visible light for the photocatalytic process,which greatly enhances the efficiency of the compound to degrade tetracycline.The photocatalysis experiments in different water quality showed that the organic matter in the water has a great influence on the degradation of tetracycline.In order to explore the role of different active species in the degradation process of tetracycline,NBT ultraviolet-visible spectroscopy,fluorescence method,electron spin resonance（ESR）method and active species capture method were used to explore the types and yields of active species,and found that·O₂^-and h⁺play a major role in the reaction process.According to the signal strength of·O₂^-and·OH,it shows that the production of·O₂^-and·OH in MOCN has a greater increase compared with CNNS.According to various characterizations and test results,the possible pathways and possible pathways of photocatalytic degradation of tetracycline are speculated.mechanism.In addition,the MOCN composite material has a stable crystal structure and good recycling ability,and has great application potential in the field of photocatalysis.