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URN etd-0804106-160624 Statistics This thesis had been viewed 2807 times. Download 270 times. Author Yen-Ling Chen Author's Email Address No Public. Department Materials Engineering Year 2005 Semester 2 Degree Master Type of Document Master's Thesis Language English Page Count 99 Title Fabrication and Properties of Nano Hybrid SnO2/CNTs Gas Sensor Keyword Gas Sensor CNTs SnO2 SnO2 CNTs Gas Sensor Abstract Recently, due to the industrial development and environmental protection pay much attention and various kinds of exhaust gas increase. The noxious gases such as CO, CO2, SO2 and NO2 control in the atmosphere. They are very toxic for human body and moreover with indirect harm to the environment such as main acidic species in acid rain. By producing the nanocrystalline materials decrease the material consumption and pollutant of environment. In this study, carbon nanotubes good conductivity at the room temperature combine with SnO2 high sensitive to gas and make gas sensor toward high response, easy manufacture and carry convenient.
Carbon nanotubes are nanostructures with remarkable electronic and mechanical properties. Potential applications of CNTs include microelectronic devices, cold cathode flat panel displays (FDP), hydrogen storage, quantum wires, tips for scanning probe microscopes and high power electrochemical capacitors. CNTs are ideal materials for adsorption and detection of gas due to their hollow center, nano-scale size, large specific surface area, and good conductivity at the room temperature. In this study, the hybrid CNTs with MOS material will be synthesized and examined its sensing properties. By sol-gel method using the precursor of Tin (Ⅱ) chloride, tin oxide is coated on acid-treated multi wall carbon nanotubes. After heat treatment at temperature 300℃ or 400℃, SnO2 particles form on the surface of carbon nanotubes with the sizes from about 3 to 15 nm. The contents of Tin (Ⅱ) chloride in solution are used to adjust the thickness of SnO2 films on carbon nanotubes. The characteristic of this hybrid materials are analysis by X-ray diffraction, SEM, HRTEM, and TGA-DTA. The pure SnO2 and SnO2/MWCNTs are separated coated on the Au electrodes printed alumina substrates in dry atmosphere at room temperature. Hybrid SnO2/MWCNTs sensor heated at 400℃ for one day to stabilize the structure of sensor. Nano hybrid SnO2/MWCNTs and SnO2 sensors detect various concentrations of NO2 from 10 to 100 ppm at different working temperatures of 50℃, 100℃, 150℃and 200℃.
Experimental results indicate it is possible to coating the nano SnO2 on the surface of carbon nanotubes by the sol-gel method. Sensitivities of SnO2/MWCNTs (A4) and (B1) are enhanced and the optimum working temperature is about 150 ℃. It shows the hybrid SnO2/MWCNTs decrease the sensing operation temperature and enhance the gas sensitivity for NO2 gas at room temperature.
Advisor Committee Hong-Ming Lin - advisor
Files Date of Defense 2006-07-07 Date of Submission 2006-08-04