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.