添加鹽類輔助合成二氧化鈦奈米線

本實驗以商業化的二氧化鈦奈米顆粒作為起始物，藉由添加鹽類的輔助合成技術成功地利用微波水熱法製備出高產率的二氧化鈦奈米線。添加鹽類（一價陽離子：NaCl、KCl、NH4Cl，二價陽離子BaCl2以及CaCl2）的不同操作參數，如鹽類添加與未添加的比較、起始原料與鹽類的比例、添加鹽類在低觸媒濃度(4M)合成的可行性以及鹽類對界達電位的影響在本研究獲得討論，所有合成的產物使用電子顯微鏡（SEM）觀察其表面結構、表面吸附分析儀（BET）量測其比表面積、X光繞射儀（X－Ray）觀察材料的晶相及奈米粒徑及電位量測儀測量其界達電位。根據實驗結果顯示所有添加的鹽類之中以NH4Cl可獲得最小的奈米線直徑(約50－80 nm)、長度可達數個μm以上，且原先的比表面積(300 m2/g)可大幅提升至372.60 m2/g。此鹽類輔助添加技術不僅可降低觸媒所使用的濃度，亦可提升奈米線合成的產率，因此，比傳統水熱法以及微波輔助合成更適合用於大量生產。此外，由於奈米線的製備方法簡單，並且所合成的奈米線容易藉由離子交換方式可移除鹽類殘餘的陽離子，故不會影響最終產物的幾何形狀及組成，若再經400 ℃鍛燒處理2 h即可轉變成具有anatse晶相的二氧化鈦奈米線。

關鍵字

微波水熱法；鹽類；二氧化鈦奈米線

並列摘要

This experiment was used commercial titanium dioxide as raw material, and different operate parameters (monovalence cation : NaCl, KCl, NH4Cl, Bivalent cation : BaCl2, CaCl2). The difference between with and without adding salts, the ration of raw material and salts, and zeta-potential influence by salts also discussed in this research. The nanowire products were characterized in several ways: scanning electron microscopy (SEM) to study the surface structure; Brunauer-Emmett-Teller (BET) method to estimate the specific surface area; X-ray diffraction (XRD) to determine the crystal phase; and with a zetasizer to measure zeta potential. According to the results, the mean nanowires diameter is about 50－80 nm and the length is about several μm. After adding NH4Cl, the specific area can increase to 372.60 m2/g. Adding this salt not only decrease the concentration of NaOH but also increase the yield of nanowires. Hence it’s better using in synthesize a great quantity of nanowires than traditional hydrothermal method. Furthermore the synthesize method was very simple, and the residual cation of products can be removed by ion-exchange. The geometry shape and composition of final products won’t change and after calcined at 400 oC in 2 h the TiO2 nanowires with anatase phase can be produced.

並列關鍵字

salt ； microwave ； nanowire

參考文獻

[48] 鍾錦軍，微波輔助水熱法合成二氧化鈦奈米線及形成機構之探討，中原大學，2008

[4] Pelagia I. Gouma and Michael J. Mills. Anatase-to-Rutile Transformation in

Titania Powders . J. Am. Ceram. Soc., 84 [3] 619–22 (2001)

[6] Ou H. H. , Shang Lien Lo and Ya Hsuan Liou . Microwave-induced titanate nanotubes and the corresponding behaviour after thermal treatment . Nanotecnology . 18 (2007)175702

[7] Dhage, S. R.; Khollam, Y. B.; Potdar, H. S.; Deshpande, S. B.; Bakare, P. P.; Sainkar, S. R.; Date, S. K. Effect of variation of molar ratio (pH) on the crystallization of iron oxide phases in microwave hydrothermal synthesis. Materials Letters 2002, 57, 457.

國際替代計量

添加鹽類輔助合成二氧化鈦奈米線

未授權

主題瀏覽