二氧化鈦奈米粒子在有機氣體壓電晶體感測器之應用

Application of TiO2 nanoparticles on piezoelectric crystal sensor for organic gases

江宜庭(Yi-Ting Jiang)

指導教授 ： 施正雄

國立臺灣師範大學/理學院/化學系/碩士(2005年)

摘要

本文是發展並應用TiO2奈米粒子為塗佈物製成壓電晶體感測器去吸附各種有機氣體，當有機氣體吸附在塗佈物上，增加的質量將造成壓電晶體感測器的震盪頻率下降，藉由觀察共振頻率的改變量來達到偵測有機氣體的目的。本研究自行組裝氣體壓電晶體感測器，並使用旋轉塗佈法(spin coating)在晶片電極表面塗佈nano-TiO2/PEG來偵測乙醇、正丁醚、乙醛、丙酮、乙酸、苯、正丙胺、1-己烯、1-己炔等揮發性有機氣體。
在實驗中，首先鑑定nano-TiO2物理性質，包括UV/Vis.吸收光譜、XRD、SEM。接著探討各種揮發性有機氣體對nano-TiO2壓電感測器所造成頻率變化的影響，包括塗佈量效應、濃度效應、分子量大小、異構物的立障效應等。nano-TiO2/PEG的最佳塗佈量固定約為8μg，偵測訊號較好的是乙酸、1-己烯、乙醛、1-己炔，在脫附訊號方面，乙醛和1-己烯的脫附速率比其他有機物要來得慢，而nano-TiO2壓電感測器對有機氣體都具有不錯的偵測下限，可達ppm。對醇類而言，化合物的分子量愈大，感測訊號強度就愈大，分子量大小和訊號呈正比關係上升；立障大小也會影響訊號強弱，頻率變化量依次為1-propanol＞2-propanol和1-butanol＞sec-butanol＞ iso-butanol＞tert-butanol。
本研究把nano-TiO2應用在石英壓電感測器上，對於常見的有機氣體有不錯的感測訊號，加上感測系統體積小、易自行組裝、成本低廉及靈敏度高的優點，可以廣泛應用在化學工廠和工業上對有機氣體之檢測。

關鍵字

壓電晶體感測器 ； 二氧化鈦 ； 奈米

並列摘要

A piezoelectric(PZ) crystal sensor with TiO2 nanoparticles coating was developed and applied to adsorb various organic vapors. When organic vapors are adsorbed on the coated material, the increased mass will result in a decrease of resonant frequency of PZ crystal sensor. By observing the change of the resonant frequency, we can detect these organic vapors. In this study, a home-made computer interface for data processing was designed to detect common organic gases such as ethanol, di-n-butyl ether, acetaldehyde, acetone, acetic acid, benzene, n-propylamine, 1-hexene and 1-hexyne.
At first, the physical properties of TiO2 nanoparticles was investigated with UV/Vis. spectrum, XRD and SEM. The effects of coating load, concentration, molecule mass, steric hindrance of volatile organic gases on the frequency response of PZ gas sensor were also studied. The optimum coating amount of nano-TiO2/PEG was found be around 8μg. Among these organic vapors, Acetic acid, 1-hexene, acetaldehyde and 1-hexyne showed better responses, and also found that acetaldehyde and 1-hexene had lower desorption rate. The PZ crystal sensor showed good detection limit of ppm level. For alcohol, the larger molecule mass gave, the greater signal responded. Moreover, the frequency shifts depended on steric hindrance were in the order： 1-propanol＞2-propanol；1-butanol＞sec-butanol＞ iso-butanol＞tert-butanol.
The PZ crystal sensor based on TiO2 nanoparticles developed in this study had good responses for common organic gases. Furthermore, the sensor which is small, self-assembled easily, cheaper and high sensitivity could be applied for detection of organic gases in the chemical laboratory and industry.

並列關鍵字

QCM ； TiO2 ； nanoparticles