| In recent years, the constant improvement of the modern economy and the rapid development of science and technology have caused that the problem about environment pollution and protection has received more and more attention, and led to that the development and application of sensor continuously extend. Gas sensor has the advantages of simple structure, low cost and high sensitivity, so it is one of the most widely used type in chemical sensor, and it is extremely important to monitor all kinds of poisonous and harmful, flammable and explosive gas in environment. Selection of gas sensitive materials have very important influence on the performance of gas sensor, so to find the right gas sensitive material to improve performance of sensor has been the main research direction and research purposes.Multi-walled Carbon Nanotubes(Multiwalled Carbon Nanotubes, referred to as MWCNTs) is one kind new type of one-dimensional nanomaterials with unique hollow structure, and it has the characteristics of large surface area, good adsorption performance and conductive properties that metallicity and semiconductor property can vary with diameters and chiral, that makes it has obtained a lot of development in the application of electrochemical sensor.Ionic liquids(Ionic liquids, referred to as IL) is a new kind of green solvents that is completely composed of anion and cation, and it has advantages of negligible vapor pressure, excellent thermal and chemical stability, nonflammable, non-volatile and high electrical conductivity, as well as can absorb and dissolve a large number of inorganic and organic matter, more importantly it can adjust the solubility of ionic liquids to other substances by changing anion and cation, so it is often used as green solvents and in production of chemical sensors.Acid oxidized carbon nanotubes and different kinds of ionic liquids were prepared firstly in this paper, after respectively characterized, they were detected on gas sensing property; then the carbon nanotubes/ionic liquid gel with different carbon nanotube content and different preparation of carbon nanotube content and different anionic species was prepared, and they were characterized by FT-IR and TGA. After that, gas sensitive performance of carbon nanotube/ionic liquid gel as gas sensitive material of gas sensor was detected on gas-sensitivity test system, and the influence of ionic liquid species and carbon nanotube content on the sensor performance was found, and the sensor experimental condition was optimized, then the best test temperature and optimum responsive gas was found. The main research work is as follows:1. Three kinds of common room temperature ionic liquids(1-butyl-3-methyl imidazolium chloride(BmimCl), 1-butyl-3-methyl imidazolium tetrafluoroborate(BmimBF4), 1-butyl-3- methyl imidazolium hexafluorophosphate(BmimPF6)) were snythesized by conconsulting documents in this paper, then the prepared compounds were characterized by FT-IR, and its thermal stability was analyzed by TGA.2. Carbon nanotubes was oxidized with acid treatment to improve the activity of carbon nanotubes and their compatibility and stability in ionic liquids, thus to improve gas sensitivity of gel composite, and acid oxidized carbon nanotubes was characterized by FT-IR, and its thermal stability was analyzed by TGA.3. The compound of ionic liquid and acid oxidized carbon nanotubes was grinded wetly in agate mortar to prepare different content of gel, then the gel was characterized by FT-IR, and its morphology and thermal stability was studied using SEM and TGA.4. Gas sensor was fabricated with the prepared gel as gas sensitive material, then the gas sensitivity to formaldehyde, acetone, ammonia, acetonitrile and ethanol was detected respectively, and the test conditions and results of gas sensor were analyzed to find the best response condition. |
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