Preparation,Modification And Photocatalytic Performance Of Bi-baced Photocatalysts

Among the semiconductor photocatalysts,Bi-based photocatalysts have attracted more and more attention because of their excellent photocatalytic performance.Thus,exploiting new preparation and modification methods to control the morphology and structure of Bi-based photocatalysts have important significance on research of the relationship between the morphology,structure and photocatalytic performance.In this paper,the controllable preparation and modification of several new Bi-based photocatalysts can be achieved with changing the type and ratio of raw materials,and the photocatalytic performance of the Bi-based photocatalysts were also investigated.The main work and results are summarized as follows:?1?BiVO₄ hollow fibers,Ag⁺/Ag/BiVO₄ and Ag/BiVO₄ hollow fiber composites were prepared by using cotton fibers as the templates.The effects of calcination temperature and silver modification on the structure,morphology and photocatalytic performance of the hollow fibers were investigated.The results showed that,among the BiVO₄ hollow fibers prepared at different calcination temperatures,the sample obtained at 500?had the highest degradation efficiency of Methylene blue.After the modification of silver,the composites had an enhanced photocatalytic performance.The Ag⁺/Ag/BiVO₄ hollow fibers had the highest degradation efficiency of Methylene blue with a removal of 97%in120 minutes under visible light irradiation.?2?NaBiO₃/Bi?C₂O₄?OH and NaBiO₃/Bi₂O₂CO₃ composites were prepared at room temperature.The structure and morphology of the products could be controlled by changing the ratio of raw materials.The photocatalytic activity of NaBiO₃/Bi?C₂O₄?OH and NaBiO₃/Bi₂O₂CO₃ composites was investigated by the degradation of Rhodamine B under visible light irradiation.The results indicated that the NaBiO₃/Bi?C₂O₄?OH composites had a better visible light photocatalytic activity than the pure NaBiO₃ and Bi?C₂O₄?OH.Among the NaBiO₃/Bi₂O₂CO₃ composites with different molar ratio,the sample obtained with the molar ratio 0.2 of H₂C₂O₄ to NaBiO₃ showed the highest photocatalytic activity for degradation of Rhodamine B under visible light irradiation,the decomposition efficiency of Rhodamine B was about 96%after irradiation for 60 minutes.?3?A new nanostructured Na₃Bi?PO₄?₂ material and Ag₂O/Na₃Bi?PO₄?₂ composites were prepared by a hydrothermal method.The morphology and composition of the products could be controlled by changing the ratio of raw materials and types of phosphate.The photocatalytic activity of Na₃Bi?PO₄?₂,Ag₂O and Ag₂O/Na₃Bi?PO₄?₂ composites was investigated by the degradation of Rhodamine B under visible light irradiation.The results showed that the decomposition efficiency of Rhodamine B over Ag₂O/Na₃Bi?PO₄?₂composites was about 85%after irradiation for 40 minutes.?4?Self-doped truncated bipyramidal Bi₂O₂CO₃ was synthesized by a hydrothermal method,and thus the one-step preparation and modification of Bi2O2CO3 were achieved.The amount of the doped Bi⁵⁺,percentage of{001}exposed facets,thickness and band gap of truncated bipyramidal Bi₂O₂CO₃ could be controlled easily by adjusting the molar ratio of NaHCO3 to NaBiO3.The photocatalytic activity of the samples was also investigated.The results indicated that the Bi2O2CO3 obtained with the molar ratio 8 of NaHCO3 to NaBiO₃ showed the highest photocatalytic activity.