Integration of ceramic catalyst on micro-thermoelectric gas sensor

An integration technique of dispensing ceramic paste containing the particles of Pt loaded on alumina (Pt/alumina) on thin membrane of microthermoelectric hydrogen sensor ( mu-THS) has been developed. By changing the concentration of the catalyst particles in the paste, the viscosity of the paste was controlled to prepare the thick film catalyst of different thicknesses. The thickness of the catalyst was closely related to both the gas sensing performance and its temperature dependency of the mu-THS device. The sensor device with the moderate concentration of the Pt/alumina catalyst particle in the paste, 3.8% (v/v), showed the voltage signal of ca. 10 mV for the gas mixture of hydrogen/air, I % (v/v) H-2 in air at catalyst temperature of 100 degrees C. The performances of the mu-THS with ceramic thick film catalyst and Pt thin film catalyst have been compared, and the influences of CO gas on their sensing performance have been investigated using in situ FT-IR test method. The better gas oxidation performance of the ceramic thick film than that of Pt thin film could remove out the adsorbed CO on the catalyst surface. (c) 2006 Elsevier B.V. All rights reserved.