The Preparation And The Photocatalytic Activity Of Bi₂O₂CO₃ Composite Materials

With the growing energy shortages and the increasing environmental degradation,semiconductor photocatalytic technology as a kind of green environmental technology,can degrade organic pollutants in air and water to H₂O,CO₂ and some harmless inorganic small molecules,which thereby widely arouses people's concern.In recent years,bismuth based photocatalyst was widely researched and rapidly developed.Due to the unique layer structure,good photocatalytic activity,easily recycled and non-toxic properties,Bi₂O₂CO₃ as a kind of typical of Aurivillius oxide exhibits peomising application in the aspect of environmental restoration and photocatalytic degradation,and brings much attention.In this paper,two kinds of photocatalysts?BiPO₄/Bi₂O₂CO₃ and Bi₂O₂CO₃/ZnFe2O₄?were prepared by hydrothermal method,and RhB was chooseed as simulated dye to investigate the photocatalytic activity of Bi₂O₂CO₃ composite materials.To investigate the structure and property of the samples,the as-prepared samples were characterized by XRD,SEM,HRTEM,BET,XPS,PL,FTIR,UV-vis methods and trapping experiment.The possible mechanisms of the enhanced photocatalytic performances were proposed on the above results.In this paper,the main research contents and conclusions are as follows:?1?Nanoplate-like BiPO₄/Bi₂O₂CO₃ heterostructured photocatalyst with different loading amounts of BiPO₄ was successfully prepared by a two-step hydrothermal method.The photocatalytic activities of BiPO₄/Bi₂O₂CO₃ composite,pure BiPO₄ and Bi₂O₂CO₃ were evaluated by the degradation of RhB solution under UV light.The results indicated that the photocatalytic activities of all the as-prepared BiPO₄/Bi₂O₂CO₃ composites clearly showed much higher than individual Bi PO4 and Bi₂O₂CO₃.Among the composites,the 3% BiPO₄/Bi₂O₂CO₃ showed the highest photocatalytic activity and the degradation efficiency could reach 92.6 % within 40 min,which was about 1.7 and 2.3 times higher than that of pure Bi₂O₂CO₃ and BiPO₄,respectively.The improved photocatalytic activity of all the BiPO₄/Bi₂O₂CO₃ composites could be attributed to the formation of special heterojunction structure,which benefited the interfacial charge transfer and improved the separation efficiency of photogenerated electron–hole pairs.?2?The heterostructured photocatalyst of Bi₂O₂CO₃/ZnFe2O₄ was successfully synthesized by two-step hydrothermal route.The ZnFe2O₄ nanoparticles were first successfully synthesised using CTAB as template and ethylene glycol as solvent at 200 ?by hydrothermal method.Secondly,we synthesize nanoparticles ZnFe2O₄ modified Bi₂O₂CO₃/ZnFe2O₄ heterostructure photocatalyst at 180 ?.The effects of the amounts of Zn Fe2O₄ loading amount on the influence of the Bi₂O₂CO₃/ZnFe2O₄ compound photocatalyst were investigated and the optimal proportion was obtained.When Bi₂O₂CO₃ and ZnFe2O₄ quality ratio is 1:1,the photocatalytic effect of Bi₂O₂CO₃/ZnFe2O₄ heterostructure photocatalyst shows the best performance and the degradation of rhodamine B reach 92.2 % under the UV light within 80 min.This may be attributed to the formation of the heterostructure which is helpful to promote electron transfer and transportation,further improving the photocatalytic performance.