掺铁纳米二氧化钛的制备表征及其光催化效能研究

【作者】 杨娟玉；

【导师】 陈晓青；

【作者基本信息】 中南大学 ， 分析化学， 2004， 硕士

【摘要】 本文采用溶胶—凝胶法制备出纯纳米二氧化钛和掺铁纳米二氧化钛溶胶溶液，用冷冻干燥的方法干燥成干凝胶粉，在不同的温度下煅烧生成纳米粉末。首次采用冷冻干燥的方法干燥溶胶溶液，有效地解决了溶胶粒子的粒径受干燥过程中温度影响大的难题，且干燥时间大大缩短；在钛酸四丁酯用量为10ml的情况下，实验得出最佳反应温度为40℃、反应体系加水量为60ml、溶液的pH值为1.0、最佳煅烧温度为400℃、最佳掺铁量为0.05％。 采用差热—热重法、激光粒度分析法、X射线衍射线法和扫描电镜对煅烧后的纳米粉末结构进行表征。由测定结果可知，在400℃下，纯纳米二氧化钛为锐钛矿型、粒径为70.1nm、比表面积为72.4m~2／g的球形粒子；0.05％的掺铁纳米二氧化钛为锐钛矿型、粒径为63.4nm、比表面积为82.2m~2/g的球形粒子。此外，掺铁使得纳米二氧化钛的晶相转变温度提高，同时也抑制了粒子在煅烧过程中的粒径生长和团聚。从紫外一可见分光光度分析可知在整个可见光区掺铁纳米二氧化钛比纯纳米二氧化钛的吸光度增强，整个吸收边带红移，说明掺铁有利于对可见光的吸收。对苯酚水溶液的光催化降解研究结果表明，紫外光照4h后掺铁纳米二氧化钛的光催化活性比纯纳米二氧化钛提高了1.6倍。更多还原

【Abstract】 The nanocrystalline iron-doped titania was prepared by sol-gel technique. Thermogravimeteric and differential thermal analyse, X-ray diffraction, scanning electron microscophy, laser diffraction particle size analyzer and UV-Vis spectrophotometer technology were used to characterize the product.From the results of experiments, we draw the conclusions that the optimal reaction temperature is 40 , the water dosage is 60ml, the pH value is 1.0, the optimal calcining temperature is 400 and the best iron content is 0.05%. The particle size is 70.1nm and the surface area is 72.4 m2/g from the sample of pure anatase titania calcined at 400 for 2h. On the other hand, the particle size is 63.4nm and the surface area is 82.2 m2/g from the sample of 0.05% iron-doped anatase titania calcined at the same temperature. Moreover, the iron implantation decreases the grain growth rate. Finally, the absorption edge of the iron-doped titania has a red shift and the sample also has a stronger absorption than the pure titania in the visible region. Since the iron-doped titania can absorb light in a wider range of wavelength and utilize more light energy than pure titania. It follows that a higher photocatalytic activity should be expected in iron-doped titania. The same result is further confirmed by the result of photocatalytic activity of phenol and living wastewater.更多还原