氧化铋氧化钛纳米管复合材料的制备及其表征.doc

毕业设计（论文）题 目：Bi2O3/TiO2纳米管复合材料的制备与表征Bi2O3/ TiO2纳米管复合材料的制备与表征 摘 要纳米二氧化钛是一种性能优异，广泛用于环境保护的光催化剂，但由于其带隙较宽（3.2eV），只能被波长较短的紫外线激发，故对太阳能的利用率较低；而且，由于光生电子与空穴的复合，导致其光量子效率降低。半导体复合是克服上述不足的一种良好纳米二氧化钛改性方法。本论文以二氧化钛粉体为前驱体，以10mol/L的NaOH溶液为强碱介质，采用水热法合成二氧化钛纳米管。采用XRD、TEM对样品进行表征，初步分析了二氧化钛纳米管的形成过程及机理。采用化学沉积-锻烧法制备了Bi2O3/TiO2纳米管复合材料，并用XRD、TEM、UV-vis、荧光光谱对其物相、形貌、光谱特性进行表征。实验结果表明，随着Bi2O3负载量的增加，TiO2纳米管中金红石相含量增多。当Bi2O3含量为3.0%时，可以获得牢固附着在TiO2纳米管表面，粒径约3nm，高度分散的Bi2O3纳米粒子。Bi2O3抑制了TiO2纳米管光生电子和空穴的复合，降低了TiO2纳米管的荧光强度。UV-vis分析结果表明，负载1%的Bi2O3后，TiO2纳米管的吸收峰从380nm移至400nm，增强了TiO2纳米管对可见光的吸收。关键词：TiO2纳米管 ；复合半导体；光电效应；光催化性能 Preparation and characterization of synthesis of bismuth dioxide - titanium dioxide nanotube compositesABSTRACTTitanium dioxide is an excellent photocatalyst which has widely used in environmental protection. However, it can only be excited by ultraviolet due to its wide band-gap (3.2 eV). And the high recombination rate of photogenerated electron/hole pairs of TiO2 results in lower light quantum efficiency. Combination with other semiconductor on titanium dioxide is a good method to overcome those shortcomings mentioned above. In the present thesis, TiO2 nanotubes were prepared via a hydrothermal approach using TiO2 powder as raw materials and 10 M NaOH solution as alkaline medium. XRD and TEM were applied to characterize TiO2 nanotubes. The formation mechanism of TiO2 nanotubes was discussed. A chemical deposition-calcination approach was proposed to fabricate Bi2O3/TiO2-NTs composites with TiO2-NTs prepared via a hydrothermal method as substrates. The samples were characterized by XRD, TEM, PL, and UV-vis. It was found that Bi2O3 nanoparticles with sizes of 3nm were highly and tightly dispersed on the surface of TiO2-NTs when the content of Bi was 3.0 at. %. Combination of Bi2O3 could effectively prohibit the recombination photogenerated electron/hole pairs. The absorption edge of TiO2-NTs shifts from 380 nm to 400 nm when 1.0 at. % Bi2OKey words: TiO2 nanotube； synthesis semiconductor； pho