利用超臨界二氧化碳快速膨脹法製備奈米二氧化鈦之研究

Synthesis of TiO2 Using Rapid Expansion of Supercritical Solutions (RESS) Method

陳寶祺(P. C. Chen) ； 呂冠蓁(K. C. Lu)

《鑛冶：中國鑛冶工程學會會刊》 54卷2期 (2010/06) Pp. 61-67

https://doi.org/10.30069/MM.201006.0005

摘要

本研究利用超臨界快速膨脹法（RESS）製備TiO2。以原鈦酸四丁酯（Tetra-n-butyl-orthotitanate, TBOT）和異丙醇（Isopropyl Alcohol）稀釋成0.4M溶液，之後以高壓泵打入超臨界二氧化碳合成TiO2先軀體，利用TGA確定煅燒溫度為450℃，而以SEM、XRD分析，固體晶型粒徑與組成，並以UV及PL鑑定光譜吸收強度及放射強度，以進一步鑑定TiO2之特性。操作變數為溫度、時間與壓力，以探討變數對於TiO2先軀體及TiO2形成的影響。操作溫度45~85℃，時間2~8小時而壓力1500~2500psi。由結果顯示以RESS所製備之TiO2先軀體有團聚現象，而經煅燒後所得之粒徑為奈米級，由XRD數據及Scherrer方程式顯示TiO2之粒徑在16-46nm左右符合奈米光觸媒特性，本實驗應用田口實驗設計有效減少實驗次數將原本三因子三水準需做27次簡化成9次，能夠讓研究快速得到較佳的設計參數，由田口實驗數據分析S/N因子反應圖所得結果顯示壓力在2500psi、溫度65℃反應時間4小時為本實驗最佳條件。

關鍵字

超臨界二氧化碳 ； 快速膨脹法 ； 奈米二氧化鈦

並列摘要

TiO2 was synthesized using Rapid Expansion of Supercritical Solutions (RESS) method. A mixture of tetra-n-butyl-orthotitanate (TBOT) with isopropyl alcohol was prepared at a concentration of 0.4M. The mixture was introduced into a high pressure carbon dioxide supercritical fluid reactor to obtain TiO2 precursor. The decomposition temperature of the precursor was 450℃observed by TGA instrument analysis. Calcined solids were examined by SEM and XRD to determine the particle size and composition. The absorption spectrum and emission spectrum were determined by UV and PL, respectively. Three major process variables, temperature, time and pressure were varied in the experiments to study the impact of these variations on the TiO2 synthesis. Result showed that the TiO2 precursor appeared in agglomeration before calcination. After calcination, the TiO2 agglomerates were decomposed to 16 to 45nm nanosize particles as estimated by Scherrer's equation and XRD data. We used Tagchi methods for experimental design to search for minimal number of experiments and optimal process parameters. S/N factors analysis of Tagchi experimental data showed that the best TiO2 synthesis condition is 65℃, 4 hr, and 2500 psi.