Syntheses and Modifications of TiO2 Nanobelts by Hydrothermal Method

水熱法合成二氧化鈦奈米帶及其改質

余思縈(Shih-Ying Yu)

指導教授 ： 陳力俊

國立清華大學/工學院/材料科學工程學系/碩士(2009年)

摘要

二氧化鈦是最有效率的光催化材料之一。由於它擁有長時間的穩定性，無毒性及優越的光催化活性，目前已經被廣泛的使用。本研究主要著重在探討利用水熱法及離子交換法生長金屬摻雜的二氧化鈦奈米帶，並且探討其特性。
產量高、形態一致的鎢摻雜與二氧化釩修飾的二氧化鈦奈米帶成功地經由兩步驟合成被製造出來。成長的參數，例如：起始材料的的結構、鹼性溶液的種類及濃度、反應溫度及時間皆依照不同的摻雜金屬而試驗出各自的最佳化條件。此外，鎢摻雜的二氧化鈦奈米帶也可經由一步驟結合水熱法及離子交換法的方式合成。不同的摻雜原始材料量對於成長以及相的影響將被討論。
此研究中，測量了金屬摻雜二氧化鈦的紫外-可見光光譜。結果可以發現，經過金屬摻雜的二氧化鈦奈米帶擁有比純二氧化鈦奈米帶更小的能帶，這個性質可以改善其對於可見光的吸收。
對於酒精氣體感測的性質在此研究中也同時被證明。在攝氏150度時，對不同酒精氣體濃度的感應也被測試。摻雜對於結構以及感應的性質的影響也被探討。鎢摻雜的二氧化鈦奈米帶擁有比純二氧化鈦薄膜更好的敏感性。此外，在相對性低的工作溫度下，鎢摻雜的二氧化鈦奈米帶也擁有很短的反應以及回復時間。

關鍵字

二氧化鈦 ； 奈米帶 ； 紫外-可見光吸收光譜 ； 氣體感測 ； 水熱法 ； 鎢摻雜 ； 釩摻雜

並列摘要

Titanium dioxide, known as one of the most efficient photocatalytist materials, is widely used because of its long-term stability, free from toxicity and good photocatalytic activity. This study is focused on the properties of metal-doped TiO2 nanobelts grown with hydrothermal treatment and ion-exchange.
High yield, uniform tungsten-doped and VO2-modified TiO2 nanobelts were synthesized through the two-step synthesis. The growth parameters such as the structure of raw material, the nature and concentration of alkaline solution, reaction temperature and time are optimized depending on different doping source. In addition, the preparation of tungsten-doped TiO2 nanobelts was conducted with a one-step synthesis process combining ion-exchange with hydrothermal treatment. The influences of different amount of doping source on the growth and phases of tungsten-doped TiO2 were investigated.
Ultraviolet–visible (UV–Vis) diffuse reflectance spectra of prepared metal-doped TiO2 were recorded. The doped TiO2 nanobelts possess narrower band gaps than the pure TiO2 nanobelt, which can be attributed to the enhanced absorption in the visible light region.
The gas sensing properties to ethanol were demonstrated in this work. The electrical response towards different gas concentration have been tested at 150 °C. Doping effects on structural and sensing properties were also investigated. The tungsten-doped TiO2 nanobelts was found to possess a higher sensitivity than pure TiO2 thin film. Furthermore, the tungsten-doped TiO2 nanobelts exhibited a short response and recovery time at the relative low working temperature.

並列關鍵字

Titanium dioxide ； Nanobelts ； UV-Visible Spectroscopy ； Gas sensing ； Hydrothermal Method ； W-doped ； V-doped

參考文獻

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