A study of a QCM sensor based on TiO₂ nanostructures for the detection of NO₂ and explosives vapours in air

The paper deals with investigations concerning the construction of sensors based on a quartz crystal microbalance (QCM) containing a TiO₂nanostructures sensor layer. A chemical method of synthesizing these nanostructures is presented. The prepared prototype of the QCM sensing system, as well as the results of tests for detecting low NO₂concentrations in an atmosphere of synthetic air have been described. The constructed NO₂sensors operate at room temperature, which is a great advantage, because resistance sensors based on wide gap semiconductors often require much higher operation temperatures, sometimes as high as 500 °C. The sensors constructed by the authors can be used, among other applications, in medical and chemical diagnostics, and also for the purpose of detecting explosive vapours. Reactions of the sensor to nitroglycerine vapours are presented as an example of its application. The influence of humidity on the operation of the sensor was studied.