Detection of SO2 and H2S in CO2 stream by means of WO3-based micro-hotplate sensors

Active layers of pure and Pt doped WO3 were deposited by rf magnetron sputtering on micro-hotplate substrates. SEM was used for active layer morphology characterization. The obtained devices can be used to detect traces of pollutant gases in a CO2, stream, showing reversible responses. The pure WO3-based sensors were sensitive to low concentrations of SO2 (1 ppm) in carbon dioxide while the Pt doped detected very low concentrations of H2S (100 ppb). The influences of the operating temperature and the electrode geometry have been analyzed. The results are promising for using these sensors in a low cost beverage grade carbon dioxide monitoring system. (C) 2004 Elsevier B.V. All rights reserved.