Bi_2Fe_4O_9的溶剂热法合成及其光催化性能

Solvothermal Fabrication of Bi_2Fe_4O_9 and Its Photocatalytic Properties

以硝酸铋(Bi(NO_3)_3·5H_2O)、硝酸铁(Fe(NO_3)_3·9H_2O)为原料,以乙醇-水混合溶液为溶剂,采用溶剂热法在140℃的低温下合成了单相Bi_2Fe_4O_9粉体,研究了溶剂中乙醇与水的比例对Bi_2Fe_4O_9粉体的微观结构、形貌以及光催化性能的影响。结果表明:只有当乙醇-水混合液中乙醇/水的比例在5:1和3:3之间,才能在140℃下合成单相Bi_2Fe_4O_9粉体,且随着混合液中乙醇含量的减少,单相Bi_2Fe_4O_9粉体形貌逐渐由立方形向片状转变。紫外-可见吸收光谱结果表明合成的Bi_2Fe_4O_9粉体不仅对紫外光有吸收,在可见光区域也有较强的吸收。以可见光光催化降解甲基橙(MO)研究了样品的光催化性能。结果表明,片状Bi_2Fe_4O_9粉体对甲基橙降解效果比立方形的好。

Using bismuth nitrate(Bi(NO_3)_3·5H_2O), iron nitrate(Fe(NO_3)_3·9H_2O) as raw materials, and ethanol-water mixture as solvent, the pure Bi_2Fe_4O_9 powders have been synthesized by a solvothermal method at the low temperature of 140 oC. The effects of ethanol/water(m L/m L) ratios on the microstructure, morphology and photocatalytic properties of Bi_2Fe_4O_9 powders have been investigated. The results show that only when the ratio of ethanol/water(m L/m L) are between 5:1 and 3:3, single-phase Bi_2Fe_4O_9 powders could be synthesized at 140°C. With the decreasing of ethanol in the mixture, the morphology of single-phase Bi_2Fe_4O_9 powders gradually changes from cubic to sheet shape. The results of UV-visible absorption spectroscopy indicate that the synthesized Bi_2Fe_4O_9 powders not only has a absorption in ultraviolet region, but also has a strong absorption in the visible region. The photocatalytic activity of different Bi_2Fe_4O_9 samples was investigated in the decomposition of Methylene blue orange(MO) using visible-light illumination. The results reveal that the Bi_2Fe_4O_9 microsheet exhibit higher photocatalytic activity for the decomposition of MO than cuboidal Bi_2Fe_4O_9 powders.