Hydrothermal synthesis of two dimensional WO3 nanostructures for NO2 detection in the ppb-level

This work summarizes the preparation of two dimensional WO3 nanostructures by hydrothermal method and their NO2 sensing characterization in the ppb level (90-310 ppb). WO3 ultra-thin nanoplates with 100 nm of lateral size and about 10 nm of thickness were synthesized and characterized. Hydrothermal treatment (180 degrees C, 48 hours) was carried out on tungstic acid which obtained by direct precipitation of sodium tungstate dihydrate in hydrochloric acid. The morphology of the obtained WO3 was observed by SEM and TEM and their crystal structures were determined by Xray diffraction (XRD). Thick films (similar to 5 mu m and 20 mu m) of the synthesized WO3 were prepared by screen-printing, the NO2 sensing characterizations of the sensors in the ppb level (90-310 ppb) were performed under different operating conditions (temperature from 200 degrees C to 280 degrees C and relative humidity from 0% to 100%). The sensitivity of the sensors, response and recovery times are reported and discussed. (C) 2012 Elsevier Ltd....Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.