Based Graphitic Carbon Nitride Materials:Preparation,Modification And Photocatalytic Performance

Graphite carbon nitride,as a non-metal visible light-responsive photocatalyst,has become a new research hotspot in the fields of solar energy conversion and environmental restoration.In this thesis,a series of g-C3N4-based composites were successfully prepared by co-doping and hard template-chemical deposition methods.The experimental results show that the photocatalytic activity of the composites has been significantly enhanced.The details are as follows:(1)S/K co-doped graphite carbonitride photocatalyst was prepared by the method of condensation of thiourea and dithioacetamide and post-treatment in molten salt.The prepared S/K co-doped CN photocatalyst has a needle-like nanorod structure and exhibits an excellent hydrogen evolution rate of 1962.10 μmol g-1 h-1.In addition,DFT theoretical calculations show that both S and K atoms can provide more electrons to the system,resulting in the formation of a band structure similar to a metal.K atoms can be inserted between the layers of CN and bridge adjacent two layers,resulting in the formation of charge transport channels.These results show that the S/K co-doped CN photocatalyst promotes the separation and transport of photogenerated charges,thereby improving the photocatalytic activity.(2)A new composite material(Au/3DOM CN/CdZnS)was prepared by loading Au NPs and CdZnS NPs onto a three-dimensional ordered mesoporous g-C3N4 material using a two-step synthesis method of hard template-chemical deposition.The experimental results show that the Au/3DOM CN/CdZnS photocatalyst has the characteristics of close contact interface and uniform wall thickness,which promotes the Au/3DOM CN/CdZnS photocatalyst to have a wider visible light response range and stronger photogenerated electron transfer and separation ability.These characteristics make Au/3DOM CN/CdZnS materials have excellent photocatalytic activity,which can be used for hydrogen evolution and degradation of Rhodamine B.This work will provide a new strategy to design and construct g-C3N4 composite photocatalytic materials based on 3DOM structure with excellent photocatalytic activity.