High sensitivity and fast response SnO2 and La-SnO2 catalytic pellet sensors in detecting volatile organic compounds

The characteristic and effectiveness of pure and modified tin dioxide catalytic pellets as volatile organic compound sensors are discussed. The pure and La-doped SnO2 thick film sensor pellets exhibited highest sensitivity to ethanol, methanol and acetone vapour at sensing temperature 300 °C. The highest sensitivity towards 500 ppm of ethanol, acetone and methanol was achieved by 5 at.% of La-doped SnO2 with values of ∼57, ∼55 and ∼59, respectively. The enhancement of the sensitivity of La-doped SnO2 can be explained by the increase of surface areas; decrease of crystallites sizes and the basicity of the lanthanum dopants. The response times for the developed sensors were about 13–15 s for both pure SnO2 and La-doped SnO2 illustrated a fast response sensor that could be used as VOC sensors.

Research highlights▶ SnO2 and La-SnO2 catalytic pellets were developed by using modified sol–gel method. ▶ The optimum operating temperature was 300 °C for both SnO2 and La-SnO2 pellets. ▶ The response times for both SnO2 and La-SnO2 pellets were in the range of 13–15 s. ▶ The highest sensitivity towards VOCs was achieved by the 5 at.% La-SnO2 pellet. ▶ Lanthanum in SnO2 had increased the pellet's sensitivity in detection of VOCs.