| Rapid development of Nano Science &Technology provides potential and new technology for gas detection. How to use the peculiar physical and chemical properties of nano materials for fabricating new gas detection devices has become one of the hottest spots of the present Nano Science &Technology research. In this parper, carbon nanotube (CNT) arrays were synthesized in anodized aluminum oxide (AAO) templates without the use of catalysts. The preparation, properties and application of the CNT arrays have been investigated. Moreover, nanoparticles can be detected by applying a constant trans-membrane based on anodic porous alumina nanochannels.In the 1st chapter, we generalized the peculiar properties and preparation method of AAO templates, looked back the classification of gas sensors and introduction of nano material based gas sensors. In addition, we introduced the peculiar properties, preparation method and the application of carbon nanotubes in gas detection. At last, we also introduced the harm of nanoparticles and the method of the detection.Chapter 2 mainly studied the preparation of AAO templates. The highly ordered AAO with hexagonal pore structure with nanochannel diameters of 80nm were fabricated by two-step anodization. Meanwhile, we studied the fabrication of highly ordered CNT arrays by AAO template. Large-area, vertically aligned CNT arrays were synthesized by acetone pyrolysis in an open-ended anodized aluminum oxide (AAO) template that also served as a catalyst. The morphology and structure of the as-prepared CNT arrays were analyzed by a field emission scanning electron microscope (FEI Sirion 200 FEG, American), 5.0 kV. The crystallinity of the CNT arrays was examined with a Jobin–Yvon LABRAMHR spectrometer with argon-ion laser beam focusing on the sample surface at room temperature. In order to further characterize the crystallinity of the CNTs, transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) were carried out with a JEOL 2010 transmission electron microscope. Thereinto, the catalysis of alumina of the AAO template during the CVD process might include two aspects: catalyzing thermal decomposition of acetone and catalyzing converting the carbon of the decomposition of acetone to the CNTs.In chapter 4, a sandwich-structured gas sensor based on vertically aligned carbon nanotube (CNT) arrays was fabricated and investigated. In our device configuration, CNT arrays are not only sensitive dielectric but also play the role of support posts between two parallel plates. We have investigated the response of the sensor to low concentrations of ammonia, formic acid and acrylic acid at ambient atmosphere. Our results indicated that CNT arrays-based capacitive sensor had high sensitivity, relatively short response time and reproducible recovery behaviors. Besides, compared to individual or bundles of CNTs or CNT thin films based sensor, the fabrication process of our capacitive sensor was simple and did not require any techniques such as e-beam or photolithography. The possible mechanism of the responses was also discussed.In chapter 5, we introduced highly sensitive methods for electroanalytical chemistry based on anodic porous alumina nanochannels. Well-ordered anodic aluminum oxide (AAO) templates, with uniform in size, high density and controllable properties reproducibly, can be considered as an important tool of separation and detection of analytes. The nanoparticles were transported effectively through the AAO template under the existence of an electric field. This resulted in a decrease in the trans-membrane current. We presented preliminary data that suggest that such nanochannels might form the basis for new and highly sensitive methods of electroanalysis.At the end of this paper a short conclusion for the past work and the goal for future research were made.
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