Fast detection of NO2 by porous SnO2 nanotoast sensor at low temperature.

In order to challenge high working temperature, low response and low selectivity of present NO2 sensor, porous SnO2 nanotoasts with a large surface area (79.94 m2/g) were synthesized. Thick film sensors fabricated by the SnO2 nanotoasts exhibited a high response to NO2 gas operating at room temperature. Excellent performance for NO2 sensing gas at 50 °C, included the high response of 105.2 (10 ppm), low detection limitation of 0.1 ppm, fast response within 10 s, and wide range of 0.1-10 ppm (R2 = 0.9931). These sensors also demonstrated perfect selectivity, moisture resistance and 90 days of long-term stability. SnO2 nanotoasts sensor has excellent detection ability in actual detection. The superior response of porous SnO2 nanotoasts towards NO2 was attributed to the special porous structure with large specific surface area and oxygen vacancies in sensing material, which helped adsorption of the target gas molecules onto the sensing surfaces and transfer of the charge.