Used In The Research And Application Of High Sensitivity And High Selectivity Of Detection Of Explosive Gas Nanosensors

Because of the special morphology of nano-materials , they have better even different properties with normal materials. Including of these, semiconductor metal oxide nano-materials were highly emphasized, and they have been widely used in the preparation of the gas-sensitive sensor, humidity-sensitive sensors, nano-catalysts, magnetic materials, and infrared ultraviolet-absorptive materials. In this dissertation, template synthesis, sol-gel method and hydrothermal method were developed. By these methods, we have synthesized multiple semiconductor metal oxide nano-materials, including the nanotubes, nanowires, nanotubes and nanoparticles. We analysis on the morphology to understand the principles of the reaction.The semiconductor metal oxide gas sensing materials have the follow characteristics: (1) good selectivity, they can only has significantly reaction with target in various kinds of gas, (2) higher sensitivity, (3) good working stability, (4) fast response time, (5) long service life. The different morphology also influence the gas sensing property of nano-materials.There are five chapters in this dissertations.Charpter one: A review on the property and application of nano-materials with different morphology and the synthetic methods inpreparation of nano-materials was given. The research status and application prospect of semiconductor metal oxide's gas sensing property were also be talked and the characteristics of this article's detecting gas sensing property. We introduced major test equipment and the method of testing we used.Charpter two: The raw material is tetrabutyl titanate and stannous chloride, we used the Anodic Alumina Template (AAM) and synthesized the SnO₂-TiO₂ nanotube composes through the sol-gel method. The microstructures of the composites were characterized by Scanning electron microscopy, Transmission electron microscopy, High-resolution TEM, Electron diffraction pattern, X-ray diffraction and energy dispersion X-ray spectrum. Gas-sensing tests have evidenced the nanotube composites'responses to explosive gas (including CH₄,C₃H₈,H₂ and ethanol vapor).Charpter three: The raw material is SnCl4?5H2O and SnCl₂·2H₂O. We synthesized the SnO₂ nano-material (including the nano-particles, nano-rods, nano-wires and nanotubes) through the template, hydrothermal and sol-gel method. The factors which influenced the final product including reaction temperature, time, pH and surfactant were also investigated. The final product was characterized by XRD, XPS, TEM, SEM, BET. We made the product into the gas sensor used the fabrication process of weisheng company of Zhengzhou and tested the responses to explosive gas.Charpter four: The raw material is tetrabutyl titanate, we used the Anodic Alumina Template (AAM) and synthesized the TiO₂ nanotubes using the oxidation-reduction and sol-gel method, and synthesized the TiO₂ nano-particles using the hydrothermal method. We also synthesized the ZnO-SnO₂ nanocomposite with radial morphology using the cheap ZnCl2,SnCl4?5H2O and NaOH as raw material. The factors which influenced the final product were investigated too. After characterized the nano-material, we test the gas sensing property. But the result of TiO₂ is no as good as the SnO₂, just the preparation of SnO₂-TiO₂ nanotube composes. The gas sensing property of ZnO has the wide responses to the reducing gas and the sensitivity are comparable to commercial gas sensors.