| La10Si6O27has been synthesized via solid-state reaction using Al2O3, Y2O3assintering aids. XRD confirmed that adding Y2O3to La10Si6O27could effectively preventthe formation of second phases. The relative densities and SEM images indicated that thedensification of the LSO with Y2O3was effectively improved. Electrical conductivitymeasurements indicated that the total conductivity of LSO-6wt%Y2O3at700℃was2.6times lager than pure LSO. In addition, Y2O3could significantly improve the sinteringbehavior of LSO at reduced temperatures.In this work, mixed-potential-type NO2sensors based on La10Si6O27electrolyte withCuO+CuCr2O4as sensing electrode were studied. The CuO+CuCr2O4powders wereprepared in the porous LSO layer by screen printing technique. The composition andmicrostructure of the sensor were characterized by XRD and SEM, respectively. Theproperties of the sensor for monitoring NO2in the range between25300ppm werestudied. The results showed that the sensors showed good response, recovery,reproducibility and stability. With temperature decreasing, the sensitivity （emf） increasedand reached38mV in100ppm NO2at600℃. On the basis of the complex impedance ofthe device, the sensing mechanism was confirmed to a mixed potential.Hydrothermal synthesis method was used to prepare WO3. The composition andmicroscopic morphology were analyzed by XRD and SEM. And we discussed theinfluence of additive citric acid and pH on the structure and morphology of WO3. FinallyWO3with different morphology were prepared. The nanoplate of WO3with side length100200nm and thickness2030nm and the nanorods of WO3with length of200300nmwere obtained. The synthesized WO3and commercial WO3were prepared into sensors toinvestigate the influence of morphologies on the selectivity of NO2sensors. The resultsshowed that the sensitivity of the sensors was great enhanced by using the WO3nanoplatecompared with the commercial WO3at550℃. The responses of the sensor toward NO2were slightly affected by coexistent O2, CO2, CH4, H2. |
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