The sensing behavior of SnO2-based thick-film gas sensors at a low concentration of chemical agent simulants

A semiconductor gas sensor based on SnO2 was studied using chemical agent simulants such as acetonitrile, DMMP, DPGME and dichloromethane at a low concentration range from 0.02 to 0.8 ppm at 350 degrees C. The sensing behavior of SnO2-based gas sensors that included sensitivity, response, recovery and reproducibility were investigated by using a flow measuring system. In the case of acetonitrile and dichloromethane, the sensor prepared from a precipitated small SnO2 particle (15 nm) was more sensitive than that prepared from the commercial SnO2 (40 nm). The addition of NiO or Nb2O5 promoters also increased the sensitivity of the commercial SnO2 sensor. The experimental results could be explained by the effects of particle size, pore size and promoters. The recovery of the SnO2-based sensors seemed to be possible for acetonitrile and DPGME. In the cases of DMMP and dichloromethane, the complete recovery of SnO2-based sensors was not possible because of poisoning. (c) 2005 Elsevier B.V. All rights reserved.