Solvothermal Fabrication of Bi2Fe4O9 and Its Photocatalytic Properties

Using bismuth nitrate (Bi(NO3)(3)center dot 5H(2)O), iron nitrate (Fe(NO3)(3)center dot 9H(2)O) as raw materials, and ethanol-water mixture as solvent, the pure Bi2Fe4O9 powders have been synthesized by a solvothermal method at the low temperature of 140 degrees C. The effects of ethanol/water (mL/mL) ratios on the microstructure, morphology and photocatalytic properties of Bi2Fe4O9 powders have been investigated. The results show that only when the ratio of ethanol/water (mL/mL) are between 5:1 and 3:3, single-phase Bi2Fe4O9 powders could be synthesized at 140 degrees C. With the decreasing of ethanol in the mixture, the morphology of single-phase Bi2Fe4O9 powders gradually changes from cubic to sheet shape. The results of UV-visible absorption spectroscopy indicate that the synthesized Bi2Fe4O9 powders not only has a absorption in ultraviolet region, but also has a strong absorption in the visible region. The photocatalytic activity of different Bi2Fe4O9 samples was investigated in the decomposition of Methylene blue orange (MO) using visible-light illumination. The results reveal that the Bi2Fe4O9 microsheet exhibit higher photocatalytic activity for the decomposition of MO than cuboidal Bi2Fe4O9 powders.