TiO2–SnO2 system for gas sensing—Photodegradation of organic contaminants

Catalytic photodegradation of organic contaminants by means of UV light has been demonstrated for gas sensors based on composites of TiO2–SnO2. Thin film resistive-type gas sensors of TiO2–SnO2 have been deposited at 350 °C by RF sputtering from a Ti–SnO2 target with varying surface ratio of SnO2/Ti. Photodegradation experiments of bromothymol blue by UV light have been performed by means of the optical spectrophotometry over the wavelength range extending from 300 nm to 600 nm. The influence of the UV illumination on the sensor response to 100–20,000 ppm of H2 has been investigated in situ on motor oil contaminated sensors. It has been found that sequential exposures to UV light lead to a partial recovery of the sensor signal to hydrogen.