Photocatalyst Preparation Of Bismuth, Characterization And Photocatalytic Performance Studies

Bismuth-radicle nano-structural oxides have good catalytic properties, they have obvious absorption in the visible region, suggesting that these substances are able to respond to visible light, which deal with the visible light oxidation of organic pollutants. It is necessary to improve the preparation of bismuth-radicle nano-structural oxides and their development of good performance. Bi2O3 is a new type of photocatalyst, compared with TiO2.Since the narrow band gap of Bi2O3 (2.8 eV), absorb visible light generated by the photo-excited electrons and holes, Bi2O3 can be used to degrade organic pollutants. Halogen bismuth oxide BiOX (X=F, Cl, Br, I) are new type of semiconductor materials, which has a unique electronic structure, good optical properties and catalytic performance. The photocatalytic properties of BiOX riding better than commodities TiO2 (P25). With the atomic number of halogen photocatalytic activity gradually increased, the activity of bismuth oxide iodide BiOI is the highest in recent years, it hardly reported in the literature.In summary, microwave heating is an assisted-synthesis method to prepare Bi2O3 and BiOI powder photocatalyst, we examined their photocatalytic properties. This dissertation mainly includes:Bi2O3 have been successfully prepared by microwave irradiation process and subsequent thermal treatment. The products were characterized with X-ray diffraction (XRD), scanning electron microscopy (TEM), UV-Visible diffuse reflectance spectroscopy (DRS). The XRD results showed that the sample is well crystallized as the calcining temperature increased, the products changed fromβ-Bi2O3 to pure a-Bi2O3, so the calcination temperature 300℃is the appropriate temperature to synthesisβ-Bi2O3. The products are flaky, and the diameter become longer as the calcining temperature increased and the photocatalytic activities of the different crystal Bi2O3 were evaluated by the extent of decolorization of Rhodamine B under visible-light. The DRS spectra shows,α-Bi2O3 band gap is 2.84 eV,β-Bi2O3 band gap is 2.77 eV. The result shows that the photocatalytic activity ofβ-Bi2O3 is higher than a-Bi2O3.Nonospheres of BiOI photocatalyst were prepared by microwave irradiation method using Bi(NO3)3·5H2O and KI as the starting raw material, glycol and water as the solvent. The products were characterized with X-ray diffraction (XRD), scanning electron microscopy (TEM), Scanning electron microscope (SEM), UV-visible diffuse reflectance spectroscopy (DRS). At first, the room temperature mixing method as a control experiment, the photocatalytic performance tested by the product performance is higher than room temperature mixing of microwave products. Synthesized in different solvent system to select the best solvent system, above each of them on the basis of processing parameters such as molar ratio, reaction time, reaction to adjust the power and other experiments to explore the synthesis BiOI the best conditions for photocatalytic optimal performance of the catalyst. Photocatalytic reaction was also studied the optimum amount. Microwave Synthesis BiOI better experimental conditions, KI and Bi(NO3)3·5H2O molar ratio of 0.5:1, 1:1 alcohol-water ratio, microwave power 300 W, radiation 10 min. The microspheres are composed of nano-films, thickness of the film was about 20 nm, the length was about 200 nm. The result showed that BiOI has high catalytic activities towards the degradation of RhB under visible light irradiation.