Preparation And Photocatalytic Performance Study Of NaTaO₃/g-C₃N₄/G Composite

Photocatalysis is a new technology that uses solar energy for environmental purification and energy conversion.g-C₃N₄ is the most widely studied two-dimensional material in the field of photocatalysis.It has the advantages of low price,response to visible light,non-toxicity and stable chemical properties.However,the conductivity of g-C₃N₄ is poor,the recombination of photogenerated electrons and holes is serious,and only part of visible light can be utilized,which greatly limits the photocatalytic activity of g-C₃N₄.Therefore,it is very important to modify g-C₃N₄.For example,combining g-C₃N₄ with other metals or semiconductors or developing a new composite photocatalyst,which can reduce the recombination efficiency of photo-generated charges to improve the conductivity of materials and broaden the spectral absorption range of materials.It is significantly.NaTaO₃ is a perovskite with regular cubic structure,which is very stable.Most importantly,it has a suitable valence band position.Thus,NaTaO₃ can form a heterojunction with g-C₃N₄ and transfer electrons on the g-C₃N₄ conduction band effectively to improve the separation efficiency of photogenerated charges.Graphene can significantly improve the conductivity of the material,reduce the recombination of photogenerated electron holes,and broaden the spectral absorption range of the material.The purpose of this paper is to develop a composite photocatalyst with high visible light utilization and high photocatalytic activity,and to explore its reaction mechanism.This article mainly includes the following two parts:The first part:Firstly,NaTaO₃ with regular morphology was prepared by simple hydrothermal method,then NaTaO₃/g-C₃N₄ composite photocatalyst was prepared by high-temperature calcination of low-cost urea in NaTaO₃.The results of characterization and testing indicate that NaTaO₃ is a regular cubic structure and is relatively stable.After high temperature calcination with urea,the crystal structure is not destroyed,and the photocatalytic electron hole recombination efficiency of NaTaO₃/g-C₃N₄ is greatly reduced,and the photocatalytic activity is obviously improved.Under the same test conditions,the degradation efficiency of RhB can reach 47%,which is much larger than g-C₃N₄.The second part:Firstly,the graphene oxide was prepared by the modified Hummer method,and then the NaTaO₃/g-C₃N₄/G photocatalyst was prepared by photochemical reduction with NaTaO₃/g-C₃N₄.The results of characterization and testing indicate that NaTaO₃/g-C₃N₄ is uniformly dispersed on the surface of graphene.The absorption of visible light by NaTaO₃/g-C₃N₄/G is significantly higher than that of NaTaO₃/g-C₃N₄ and g-C₃N₄,and the conductivity of the material is obviously enhanced.The recombination efficiency of the hole and electrons is further reduced.Under the same test conditions,the degradation rate of RhB was greater than 99%,much larger than NaTaO₃/g-C₃N₄ and g-C₃N₄.In summary,by using NaTaO₃,g-C₃N₄ and graphene to construct a photocatalyst with high catalytic activity,the visible light utilization efficiency and photocatalytic efficiency of the material are improved,which has a great impetus to the progress of photocatalytic technology.