Effects of Textural Properties on the Response of a SnO sub(2)-Based Gas Sensor for the Detection of Chemical Warfare Agents

The sensing behavior of SnO sub(2)-based thick film gas sensors in a flow system in the presence of a very low concentration (ppb level) of chemical agent simulants such as acetonitrile, dipropylene glycol methyl ether (DPGME), dimethyl methylphosphonate (DMMP), and dichloromethane (DCM) was investigated. Commercial SnO sub(2) [SnO sub(2)(C)] and nano-SnO sub(2) prepared by the precipitation method [SnO sub(2)(P)] were used to prepare the SnO sub(2) sensor in this study. In the case of DCM and acetonitrile, the SnO sub(2)(P) sensor showed higher sensor response as compared with the SnO sub(2)(C) sensors. In the case of DMMP and DPGME, however, the SnO sub(2)(C) sensor showed higher responses than those of the SnO sub(2)(P) sensors. In particular, the response of the SnO sub(2)(P) sensor increased as the calcination temperature increased from 400 degree C to 800 degree C. These results can be explained by the fact that the response of the SnO sub(2)-based gas sensor depends on the textural properties of tin oxide and the molecular size of the chemical agent simulant in the detection of the simulant gases (0.1-0.5 ppm).