亚铁离子的引入对Bi2Fe4O9纳米颗粒光催化性能的影响

本文通过在水热法过程中添加不同含量的FeCl₂合成了一系列Bi₂Fe₄O₉纯相纳米晶,成功地在Bi₂Fe₄O₉中引入了更多低价态的铁离子。紫外可见吸收谱数据证明FeCl₂的加入使得Bi₂Fe₄O₉的光学带隙从2.06 eV降低到1.96 eV。扫描电子显微镜照片和X射线衍射图谱均证明本文合成的样品为纯相正方形片状Bi₂Fe₄O₉纳米晶。在500 W汞灯照射下,对合成的三个Bi₂Fe₄O₉纳米晶样品(S1、S2、S3,分别对应不同FeCl₂含量x=0,0.2 mmol,0.4 mmol)进行甲基橙染料降解实验,结果表明在添加20 μL双氧水时,三个样品的光催化降解速率均最快,其中S3样品的光催化降解速率比S1、S2更快。因此在适当加入双氧水的情况下,FeCl₂的加入可有效提升Bi₂Fe₄O₉光催化降解染料分子的性能。

Effect of Ferrous Ion Addition on the Photocatalytic Performance of Bi2Fe4O9 Nanoparticles

In this paper, a series of pure-phase Bi₂Fe₄O₉ nanocrystals were synthesized by adding different content of FeCl₂ in the process of hydrothermal method, and the lower valence iron ions were successfully introduced into Bi₂Fe₄O₉. The UV-visible absorption spectrum data proves that the addition of FeCl₂ reduces the optical band gap of Bi₂Fe₄O₉ from 2.06 eV to 1.96 eV. Both the scanning electron microscope images and X-ray diffraction patterns prove that the synthesized samples are pure-phase square flakes Bi₂Fe₄O₉ nanocrystals. Three synthesized Bi₂Fe₄O₉ nanocrystal samples (S1, S2, S3, the FeCl₂ content of the three samples increased from 0 during the synthesis process, corresponding to x=0, 0.2 mmol, 0.4 mmol, respectively) were used for photocatalytic degradation of methyl orange solutions under a 500 W mercury lamp irradiation. It is found that the photocatalytic degradation rate of the three samples is the fastest when 20 μL of hydrogen peroxide is added, and the photocatalytic degradation rate of the S3 sample is faster than that of S1 and S2. In the case of appropriate addition of hydrogen peroxide, the addition of FeCl₂ can improve the performance of Bi₂Fe₄O₉ in photocatalytic degradation of dye molecules.