Preparation Of G-C₃N₄-based Composite Photocatalyst And Degradation Of Norfloxacin In Water Under Visible Light

The exploration of new stable and highly active visible light photocatalysts is the key to semiconductor photocatalysis technology.In recent years,a large number of visible light responsive photocatalysts have been successfully synthesized and put into use,but their shortcomings in terms of photogenerated electron segregation migration and light absorption are worthy of improvement.At the same time,it is also worthwhile to explore the photocatalytic mechanism of composite photocatalytic systems.In this study,graphite-phase carbon nitride（g-C₃N₄）was used as a substrate to synthesize graphite-phase carbon nitride-based composite photocatalysts by modulating the morphology of the samples using an ultrasound-assisted hydrothermal method,and the crystal structure,surface morphology and chemical composition of the samples were examined by various characterization methods,and their performance in the degradation of norfloxacin in water under visible light irradiation was investigated.The enhanced photocatalytic mechanism was investigated by valence band calculations and radical trapping experiments.The main studies in this paper are as follows.1.Ultrasound-Assisted Hydrothermal Fabrication Ag I/MFeO₃/g-C₃N₄（M=Y,Gd,La）Nano Sheet–Sphere–Sheet Photocatalysts with Enhanced Photodegradation Activities for Norfloxacin.A series of composite photocatalysts Ag I/MFeO₃/g-C₃N₄（M=Y,Gd,La）with a special sheet-sphere-sheet structure were synthesized by an ultrasound-assisted hydrothermal approach,and the enhancement of photocatalyst activity by this multi-level structure was remarkable.Among them,Ag I/La FeO₃/g-C₃N₄ was the most effective for the degradation of norfloxacin in water under visible light.The theory of a possible dual Z-scheme photocatalytic system was proposed through energy band calculations and radical trapping experiments,which effectively enhanced the separation and migration efficiency of photogenerated electrons and improved the photocatalytic activity of the system.2.Synthesis of novel ternary dual Z-scheme AgBr/LaNi O₃/g-C₃N₄ composite with boosted visible-light photodegradation of Norfloxacin.A new ternary composite dual Z-scheme photocatalyst AgBr/LaNi O₃/g-C₃N₄ was synthesized by ultrasound-assisted hydrothermal method,and its structure,morphology,chemical composition and photoelectrochemical activity were investigated.The AgBr/LaNi O₃/g-C₃N₄ composite double-Z photocatalyst was also investigated for its degradation efficiency of norfloxacin in xenon lamp irradiation,in which the AgBr loading of 3%had the highest degradation efficiency and the samples showed high stability.