二氧化鈦奈米顆粒與一維奈米材料之製備

Abstract

本研究共分兩部分，第一部分為製備 TiO2 奈米顆粒，第二部分為製備 TiO2 一維奈米材料。 第一部分，製備 TiO2 奈米顆粒共分五種方式。方法一，以四氯化鈦 (TiCl4) 為前驅物，與裂解 NaH 所得之 Na 反應得到鈦金屬，再進一步以氧氣氧化，在 673 – 1273 K 以上熱處理便可獲得具 rutile 相的 TiO2 顆粒。方法二則是將上述的鈦金屬直接浸泡於去離子水，可獲得無晶相的 TiO2 奈米顆粒。方法三，以氧氣為載流氣體將 TiCl4 帶往反應器與裂解 NaH 所得之 Na 反應可得到奈米級的片狀的 anatase TiO2。方法四為將由 NaH 裂解而來的 Na 以氧氣氧化，再進一步與 TiCl4 反應可得 anatase 與 rutile 相共存的 TiO2 奈米顆粒。方法五則是直接將 Na2CO3 與 TiCl4 反應，也可得到 anatase 與 rutile 相共存的 TiO2 奈米顆粒。 第二部分， TiO2 一維奈米材料則是利用第一部份中的方法一及方法二配合陽極處理氧化鋁 (AAO) 來製備。方法一，將 NaH 鋪於 AAO 上，經裂解後與 TiCl4 反應，得到 Ti@AAO 再進一步以氧氣氧化，並以 723 – 1273 K 的溫度做熱處理，經浸泡於 6 M NaOH 去除模板，可得到直徑200 – 300 nm，長約 60 μm 具奈米級的片狀或顆粒所組成的 anatase TiO2 一維奈米材料。方法二則是將上述的 Ti@AAO 直接浸泡於去離子水，並以 6 M NaOH 去除模板，可得到直徑200 – 300 nm 具奈米級的顆粒所組成的 anatase TiO2 一維奈米材料。

This work has two parts – the preparation of titania nanoparticles and 1D nanostructures. There are five ways to synthesize titania nanoparticles. In the first pathway, the TiCl4 was reacted with Na which was from the pyrolysis of NaH to produce air-sensitive Ti nanoparticles. The raw product was further oxidized by O2 and annealed at 673 – 1273 K to form rutile TiO2 nanoparticles. In the second pathway, the Ti mentioned above was directly dipped into D.I. water to produce amorphous TiO2 nanoparticles. In the third pathway, the O2 carried TiCl4 to react with Na decomposed from NaH to produce anatase TiO2 nanosheets. In the fourth reaction pathway, TiCl4 was reacted with Na2O, oxidized from Na , to produce mixtures of anatase and rutile TiO2 nanoparticles. In the fifth reaction pathway, TiCl4 was reacted with Na2CO3 to produce a mixture of anatase and rutile TiO2 nanoparticles. In the preparation of titania 1D nanostructures, the first and the second reaction pathways mentioned above coupled with the Na@AAO template synthesis were employed. The Na@AAO was prepared by pyrolyzing NaH on AAO. The as prepared Na@AAO was reacted with the vapor of TiCl4 to form Ti@AAO. In the first pathway, the as prepared Ti@AAO was further oxidized by O2 followed by annealing at 723 – 1273 K. After the AAO template was removed in an 6 M NaOH solution, nanosheets or nanoparticles constructed anatase TiO2 1D nanostructures (diameter = 200 - 400 nm, length = 60 μm) were obtained. In the second reaction pathway, the as prepared Ti@AAO was directly rinsed by D.I. water followed by dipping into 6 M NaOH to remove the template. The polycrystals of anatase TiO2 1D nanostructures with 200 - 400 nm in diameter and 60 μm in length were obtained.