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With the accelerating pace of recent years, China's industrialization process and the continuous improvement of people's living standards, the burning of fossil fuels in the industrial, automobile exhaust emissions, the interior decoration of the release of toxic and harmful gases caused to people's health and lives and property the threat is more and more obvious. Therefore, developed to detect and control of toxic and hazardous gas sensor has a very important significance. The main work is to study the design, compact structure, high sensitivity and good stability of gas sensors. Preparation and Characterization of departure from the NASICON material NASICON as the electrolyte, the use of sodium nitrite and a metal oxide-doped alkaline earth metal carbonate, respectively, produced a current-and hybrid-potential type gas sensor, by the characterization of materials and Preparation of NASICON material composition of the sol-gel pure, not easily compressed into tablets, potentiometric sensor is suited to the production of tubular hybrid, high-temperature solid phase prepared NASICON material containing gas sensing performance testing of the device, the following conclusions: trace impurities, easily compressed into tablets, prepared NASICON ceramics dense, uniform suitable for the production of chip-type current sensor; to high temperature solid electrolyte prepared NASICON Au alkaline earth metal carbonates doped NaNO2 as the electrode production the solid electrolyte current sensor: (1) Operating temperature 200 ° C, test devices for NO2 gas can reach 10-100 ppb; (2) After comparative experiments, Au SrCO3 doped NaNO2 as NO2 sensor electrode the maximum sensitivity; (3) 9 wt.% SrCO3 best doped proportion of change (slope) of the sensor pair of 10-100ppbNO2 gas △ I, 200 ° C working temperature, a maximum of 3.7 × 103nA; (4) sensor sensitive mechanism can be reasonably explained by the electrochemical reaction on the electrode and on the sensitive electrode occurred. Sol - gel prepared NASICON material as the electrolyte, metal oxide (Cr2O3, CuO, ZnO, WO3, NiO, SnO2, Fe2O3, Co3O4) for sensitive electrode material, design and production of a buried structure hybrid potentiometric gas sensor, the device of Cl2 has good gas sensing characteristics: (1) showed the highest sensitivity (slope) -119mV/decade, and sensor test range of 1-50ppm Cl2 sensor Cr2O3 as sensitive electrode; ( 2) sensors optimum operating temperature of 300 ℃, the potential change in value of the sensor with the logarithm of the concentration of chlorine showed good linearity; and the response time of the sensor to 10ppm chlorine within 5s recovery time of less than 10s; addition , the sensor may also exhibit good selectivity; (3) based on the structure of the traditional tube type devices pioneered Implantable devices, effectively improving the sensitivity of the sensor by changing a device structure of the sensor: deep buried sensors (Type C) the sensitivity (-270 mV / decade) was significantly greater than the simple burial type (Type B) (-157 mV / decade) and the traditional structure of the sensor (Type A) (-119 mV / decade); (4) hybrid potential theory can reasonably explain the sensing mechanism. In summary, in the production of NO2 and Cl2 sensor has the advantages of compact structure, low temperature, high sensitivity, and low cost to meet the real-time measurement of toxic gas in the atmosphere, has a broad application prospects.
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