层状结构BiOBr的形成机理及其光催化降解抗生素性能

Formation mechanism of lamellar BiOBr and its photocatalytic degradation of antibiotics

通过水热合成法片层结构溴氧化铋(BiOBr)颗粒,探究其形成机理,并在氙灯光照下以喹诺酮类抗生素诺氟沙星(NOR)为降解底物,考察BiOBr形貌结构变化对光催化性能的影响。X射线衍射(XRD)和扫描电子显微镜(SEM)分析确认BiOBr制备成功。结果表明,水热合成条件下制备的BiOBr为片层结构,随反应溶液pH值的增加,颗粒尺寸逐渐变小,且分散性越来越差,吸收带边发生蓝移,禁带宽度变大。分析水溶剂环境下片层BiOBr的形貌变化生长机理,当pH=1时,BiOBr形貌为均匀的片状结构,宽度为(3~5)μm,禁带宽度为2.93 eV,表现出最佳的光催化活性,光催化反应60 min后,NOR的降解率达到87.2%,最高降解速率常数为3.31×10^(-2)min^(-1)。

Bismuth oxybromide(BiOBr)particles with lamellar structure was synthesized by hydrothermal synthesis.X-ray diffraction(XRD)and scanning electron microscopy(SEM)showed that BiOBr was successfully prepared,and its formation mechanism was investigated.The effect of structural changes on the photocatalytic performance of BiOBr was investigated using quinolone antibiotic norfloxacin(NOR)as a degradation substrate under xenon light illumination.The results show that the BiOBr prepared under hydrothermal conditions has a sheet-like structure.As the solution pH value increases,the size of the BiOBr becomes smaller and the dispersion becomes worse,the absorption band edge is blue-shifted,and the forbidden band width becomes larger.The growth mechanism of lamellar BiOBr in water solvent environment is obtained,and it is proved that when the pH=1,the BiOBr-1ph sample prepared as uniform lame-llar structure with a width of(3-5)μm and a band gap of 2.93 eV shows the best photocatalytic acti-vity.The degradation of NOR over the above catalyst is 87.2%after 60 min of reaction,and the best degradation rate constant is 3.31×10^(-2) min^(-1).