The selectivity of quartz crystal microbalance gas sensor coated with TiO2-porphyrin nanocomposite thin films towards volatile organic compounds

High and broad selectivity is among the important properties to fabricate a good gas sensor system. We had fabricated gas sensor by coating QCM with highly selective sensing elements. Many researches have been conducted using variety of sensing elements to fulfill these criteria and porphyrin has become among the potential candidates. This paper reports the use of TiO₂-porphyrin nanocomposite as sensing element to detect ethanol, 2-propanol, acetone, cyclohexane, toluene and o-xylene vapors. Eight TiO₂-porphyrin nanocomposite thin films were prepared via dip coating method. The sensing sensitivity was based on the change in the fundamental frequency of the QCM. It was observed that all the thin films have good selectivity properties towards these gases. From the results, it shows that the metal centre of the porphyrins and ligand plays a key role on the selectivity of the sensor.