Systematic approach for the evaluation of the optimal fabrication conditions of a H2S gas sensor with Taguchi method

The Taguchi experimental design method was applied for the systematic and effective investigation of the optimal fabrication conditions of an odorous gas sensor, which would be affected by various parameters, such as a main sensing material, the materials and amounts of additives, as well as several fabrication conditions. From the results of eight experimental runs, for the evaluation of seven factors and two levels, having the equivalent effects of 128 experimental runs, the following results are derived. Most of the experimental conditions in this study showed a good sensitivity to H2S at 7.84 ppm, indicating good sensor performance could be expected at even lower H2S concentrations. As for the additives, PdCl2 and Pt mainly contributed to increases in the sensitivity of the sensor, but the amount of the additives made no significant difference to the sensor performance. In addition, a sintering temperature of 500 degreesC and mixing with distilled water for 10 min was appeared preferable from the viewpoint of sensor response time. The relationship between the sensor performance and the formation of surface crystals was verified with SEM analysis. As a consequence of the optimal fabrication conditions, the final sensor response time for the sensor was shortened to 20.06 s. (C) 2004 Elsevier B.V. All rights reserved.