The effect of Bi content on the photocatalytic performance of bismuth oxybromides
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摘要: 采用水热法和溶剂热法制备BiOBr、Bi3O4Br和Bi4O5Br2三种光催化剂,通过X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)与紫外-可见漫反射光谱(UV-vis DRS)表征光催化剂的晶体结构、表面形貌和光学性能,利用密度泛函理论计算光催化剂的能带结构和态密度,在可见光照射下,通过降解RhB考察光催化剂的活性。结果表明,Bi的含量会影响光催化剂的导带位置和禁带宽度,Bi4O5Br2光催化剂降解效果最好,能够在50 min内将RhB完全降解。自由基捕获实验证明,超氧自由基(·
${\rm{O}}_2^- $ )是光催化降解RhB的主要活性物质。Abstract: BiOBr, Bi3O4Br and Bi4O5Br2 were prepared by hydrothermal and solvothermal methods. Their structural composition, surface morphology, chemical states and optical properties were characterized by XRD, SEM, XPS and UV-vis. The band structure and density of states of the photocatalysts were calculated by density functional theory (DFT). The photocatalytic activity was evaluated by degradation of RhB. The results show that band gap and the position of conduction band is affected by Bi content. The Bi4O5Br2 photocatalyst can completely degrade RhB in 50 min. Radical-trapping experiments proves that ·$ {\rm{O}}_2^- $ is the main active species in photocatalytic degradation of RhB.-
Key words:
- BiOBr /
- Bi content /
- DFT /
- photocatalytic performance
1) #: 共同第一作者 -
表 1 三种光催化剂的一级反应动力学参数
Table 1 First-order reaction kinetic parameters of three samples
Sample BiOBr Bi3O4Br Bi4O5Br2 k/min−1 0.010 0.0367 0.0642 R2 0.979 0.991 0.982 -
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