Detection and identification of gaseous organics using a TiO2 sensor

It is well established that volatile organic compounds (VOCs) can be mineralized to innocuous organic compounds when illuminated by ultraviolet (UV) light [J. Photochem. Photobiol. A 108 (1997) 1]. The focus of this research is the development of a TiO2-based microsensor that uses these photocatalytic reactions to identify specific gaseous organic compounds and allow operation at ambient temperatures. TiO2 microsensors are produced using thick-film lithographic methods and cermet materials. TiO2 and platinum films were deposited on an alumina substrate. Tests were conducted in a closed quartz glass cell at ambient temperatures and pressures. As the sensor was exposed to a variety of gaseous organic constituents in the presence of UV light, electrical characteristics of the sensor were measured. Individual gases including methylene chloride, ethanol. benzene, acetone, xylene and isopropanol produced unique signatures as they were oxidized on the sensor surface. Sensors were renewable and reusable. (C) 2002 Elsevier Science B.V. All rights reserved.