Visible-light Photocatalytic Degradation Of Pollutants By Newly Designed G-C₃N₄/CeO₂ Composite

Photocatalysis technology currently has an increasingly broad prospect in the environmental and energy fields,and it has been an important means to effectively use solar energy to solve energy and environmental problems.Graphic carbon nitride（g-C₃N₄）is a new type of photocatalytic material with visible light responses.It has the advantages of non-toxic and harmless,simple preparation,good thermal stability and chemical stability,etc.However,g-C₃N₄ also has the problems of small specific surface area,insufficient visible light responses,and high recombination rate of photogenerated electrons and holes.In this paper,the defect of g-C₃N₄ was modified by introducing another semiconductor material CeO₂ to build a heterojunction material.The research on this subject also analyzed and tested the physical and chemical properties and photocatalytic activity of the prepared materials.Among them,XRD,XPS,and SEM characterization proved that we have successfully introduced CeO₂ into g-C₃N₄ to construct composite materials.The degradation experiments by using CA as the target pollutant also proved that the composite material has better photocatalytic activity than pure g-C₃N₄.At the same time,through the analysis of different influencing factors,we found the best compound ratio,catalyst dosage and other conditions.When analyzing the effect of the initial p H,we found that the composite material g-C₃N₄/CeO₂-3 is obviously affected by the p H when photocatalytically degrading CA.The degradation effect is good under acidic conditions and when the initial p H is alkaline,the degradation effect is more difference.Combining the nature of the pollutants and the zero potential of the material,we believe that this is due to the influence of the electrostatic repulsion on the surface of the pollutants and the catalyst.At the same time,we found that g-C₃N₄/CeO₂-3 is selective for the degradation of different pollutants.After analysis,we proposed the possible mechanism.In addition,persulfate（PDS）was added to the g-C₃N₄/CeO₂-3 photocatalytic system to improve the photocatalytic performance of the system.Through analysis and testing,after adding PDS,the degradation rate of BPA has been greatly improved,reaching 82.6%degradation in one hour.We also explored the influence of different influencing factors under this condition.It can be seen that too much PDS dosage will affect the photocatalytic degradation effect,which may be because too much PDS will consume free radicals in the system.The initial p H also has a great influence on the degradation rate,the trend is still that the degradation effect is good under acidic conditions,and the degradation effect is poor under alkaline conditions.At the same time,we analyzed the degradation mechanism of the g-C₃N₄/CeO₂-3+vis+PDS system,and explored the degradation path in it.