The Manufacture Of Testing System Of Gas-sensor And Researches Of Semiconductor Gas-sensing Materials

In this article, we focus on the assembly of testing system of gas-sensor and researches of semiconductor gas-sensing materials. According to the actual requirement, some change has been made on the basis of the traditional system to enlarge the testing range. Meanwhile, computer technology and testing system have been integrated, which is propitious to the numeralization and the picturelization of the gas-sensing test. Furthermore, we have synthesized two kinds of semiconductor gas-sensing materials according to the testing system. The gas-sensing property of the materials has been characterized by the self-maded testing system.1. A testing system of gas-sensor has been designed and manufactured which is made on the basis of traditional indirect-heat gas sensor. The testing system can be also used by the macromolecule gas-sensing materials at normal temperature.2. The operating method of the lab-used gas-sensing testing system has been introduced, including facture of gas sensor, debugging and testing. In addition, the export voltage has been transform to resistance through the simulation and transformation of relative data, which offers more reliable data to express the sensitivity.3. PANI/MnO₂ complex material has been successfully prepared by using urchin-like MnO₂ as a single template through solid state method. The structure and morphology of the complex material were characterized by IR spectrum, XRD pattern, and SEM images. The diameter of the product with sphere-like structure was from 5 to 6μm. The surface of the spheres was coarse covered with large amount of nanofibers. The sensitivity to NH₃ has been increased by 4-5 times compared with other PANI material4. Pyroxylin were used as assistant agent to synthesize flower-likeβ-Ni(OH)₂ through hydrothermal process. Then NiO crystal could be obtained through thermal decomposition of the flower-likeβ-Ni(OH)₂. Meanwhile, The flower-like morphology could be preserved during the thermal decomposition process. Series of experiments indicated that pyroxylin played a key role in the formation of the flower-likeβ-Ni(OH)₂ structure. Gas sensing test indicated that flower-like NiO is in the best working state with the heating current 1000 mA, and had a better performance when exposed to formal dehyde.