科研之友
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摘要
Bismuth oxide (Bi2O3) nanoparticles (NPs) were synthesized using a novel inert gas flow-controlled microwave (MW) combustion method. A domestic MW device was modified and used to evaporate bismuth and oxidize it in the ambient atmosphere of the MW cavity. We investigated the effect of synthesis temperature, carrier gas type (nitrogen, argon or helium), and gas flow rate on the structural, optical, morphological, and chemical properties of the synthesized Bi2O3 NPs. The X-ray diffraction analysis shows that all the NPs were of mixed polycrystalline alpha and beta phases of Bi2O3 with predominance of beta-phase. For NPs synthesized with N-2, Ar, and He as carrier gases, the average NPs size was in the range of 19-86, 25-175, and 18-133 nm, respectively. The NPs size decreased with the increase of carrier gas flow rate. Consequently, the direct band gap values of the samples increased with the increase of flow rates of the carrier gases. The band gap values for the synthesized Bi2O3 NPs were in the ranges of 3.38-3.67 eV for N-2 gas, 3.29-3.65 eV for Ar, and 3.25-3.64 eV for He. The FESEM analysis of the synthesized Bi2O3 NPs revealed the formation of plate-like structures. The energy dispersion X-ray spectroscopy analysis confirmed the purity of the NPs which contains only Bi and O. The oxidation state was investigated by the X-ray photoelectron spectroscopy and confirmed the formation of Bi2O3. The Bi2O3 NPs were coated with polyethylene glycol. The NPs have a high attenuation for X-rays and have a potential for X-ray use for X-ray contrast enhancement.
- 出版日期2014-4-5
- 单位中国石油大学（北京）
