Preparation Of Tin Dioxide And Its Doped Nanomaterials And Study On Gas Sensing Properties

Gas sensor is a kind of device, which can detect different kinds of gases atdifferent concentrations and output these signal of electrical parameters. It is widelyused in the environmental investigation, national security, food processing, family life,medical diagnosis, search and prevention and so on. Nanomaterials have uniqueadvantages in gas-sensing detection. Among them, the SnO2is likely to become thenext-generation ideal candidate materials for designing and manufacturing sensorsbecause of its good properties. And metal doping, especially rare metals doping wasproved to be effective way to improve gas-sensing properties of the device. At thesame time, higher requirements for gas sensors have made the single and single dopednano devices get more and more attention of the researchers.In the thesis, we have scientific studied the single pure SnO2nanobelt and Pd2+doping, Sb3+doped SnO2nanobelt of their gas-sensing properties. We use thermalevaporation and co-evaporation method to prepare pure and doped SnO2nanobelts.XRD, HRTEM,and SEM showed the morphology and structural characterization ofthe prepared single crystal samples. Moreover, the growth mechanism and controlgrowth of the nanobelts were discussed.The single SnO2nanobelt devices with cover template technology were fabricated,and their gas sensitive properties of the prepared devices were measured to the gasof volatile organic compounds (VOCs), including ethanol, ethylene glycol andacetone, and toxic gases, contains CO, NO2and H2S. Relatively good results haveobtained:(1) the response of Pd2+doped SnO2nanobelt is1.8times in100ppm toethanol gas, and at100ppm, and the response is8.02times to NO2gas. At the sametime, it also has a good response at room temperature, which can provide a good basisto design and implement for room temperature sensors.(2) Sb3+doped SnO2nanobeltdevice shows a huge sensitivity up to20times at room temperature to100ppm H2S.furthermore, the response to100ppm H2S at150℃is as high as56times, and has agood stability and high reliability. At the same time, the response to ethylene glycoland ethanol reached2.5times and10times, which is also very high. These provide agood basis for us to achieve high precise detection of H2S at room temperature, and itis likely to make a breakthrough and the positive significance for the detection of H2Sgas.(3) The possible mechanism of gas sensitivity were discussed.In conclusion, tin dioxide and doped single nanoscale devices were prepared with high sensitivity, room temperature response, facilitate integration, low cost, highreliability, fast response, and many other advantages. The sensors are important forVOCs and toxic gas detection.