The Synthesis and Characterization of Titanium Dioxide Nanotubes

• Main Authors: Hsin-wu Chang, 張信務
• Other Authors: Chih-hao Lee
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/25gc3d

碩士 === 國立清華大學 === 工程與系統科學系 === 92 === Titanium oxide nanotubes can be prepared in a large quantities by hydrothermal method, which is simple to follow and produce a high degree of purity of titanium oxide nanotubes. Because of the high specific surface area ratio of titanium oxide nanotubes we prepared, the photocatalytic efficiency can be raised up effectively. And the major objective of this thesis aims at the analysis and discussion of the structure and formation mechanism of titanium oxide nanotubes. There are five kinds of tools we use in this thesis for probing the structure and formation mechanism of titanium oxide nanotubes, including SEM、TEM、X-ray powder diffraction、Raman spectroscopy and X-ray absorption spectrum. From the SEM and TEM results, we observe the tube-like materials and its formation process. From the SAED result, we determine the tube axis and rolling-up axis are [010] and [001] direction respectively, and this model also can be confirmed by HRTEM result. From the XRD result, we propose the change of lattice constants. From the Raman spectroscopy, we observe the disappearance of titanium oxide anatase phase and the destruction of its vibration modes. From the XAS analysis result, we observe the bond distance and coordination numbers change for the reaction time with NaOH solution. To combine all of the experimental results above, we propose the formation mechanism which includes the rolling-up method for the most part and stacking-up method for minor importance. And the anatase (101) plane constructs the tube wall surface, the anatase (010) plane constructs cross-section surface of tube. After reacting with NaOH solution for 24 hours, the titanium oxide nanotubes which have the inner diameter of 20-70 nm, outer diameter of 30-80 nm and length of several μm are prepared.