本研究合成出自製奈米二氧化鈦 TiO2、Au/TiO2 及 Pd/TiO2 感測材料，並利用 X 光繞射 (X-ray diffraction, XRD) 及穿透式電子顯微鏡 (transmission electron microscope, TEM) 儀器將這些材料進行定性之研究，以 了解其微結構，並將此材料應用於甲醛氣體感測研究。研究項目有感測信號 (sensor response)、反應時間 (response time)、回復時間 (recovery time) 與重覆性測試 (repeatability test)。研究中發現添加 Au 與 Pd 於 TiO2 表面可以增加 TiO2 之感測信號約三倍，並降低反應時間及回復時間。本研究提出了甲醛感測之反應 機構 (sensing reaction mechanism)，期望未來能研究出學術創新及實用性高的新材料高靈敏度甲醛氣體感 測技術。

In this study, homemade nano-titania TiO2, Au/TiO2 and Pd/TiO2 were prepared as sensing materials, and using X-ray diffraction (X-ray diffraction, XRD) and transmission electron microscopy (transmission electron microscope, TEM) instrument to characterize the materials. The purpose is to understand its microstructure and sensing properties of HCHO gas. Research items are including sensor response, response time, recovery time and repeatability test. We found that the addition of Au and Pd on TiO2 can promote the sensor response of TiO2 about three times, and reduce the response time and recovery time. A sensing mechanism was proposed in this study. It can be expected in the future academic innovation and practicality developed the new materials with high sensitivity of formaldehyde gas sensing technology.