MCM-41 modified SnO2 gas sensors:: sensitivity and selectivity properties

MCM-41 modified SnO2 (SnO2/MCM-41) gas sensors were prepared by mechanically mixing SnO2 with MCM-41 (which is a novel high-surface-area mesoporous material) followed with thermal treatment in air at 700 degrees C. H-2, CO and CH4 were selected as probing gases to characterize the sensing properties of these sensors. Compared with those of the pure SnO2 sensor, SnO2/MCM-41 sensors showed enhanced sensitivities and selectivity to H-2. It was found that the SnO2/MCM-41 sensor having SnO2 content of SnO2/MCM-41 = 0.7 (weight ratio) possessed the highest H-2 sensitivity. The sensitivities to CO and CH4 were also found to be improved on the SnO2/MCM-41 sensors at much higher temperature ranges. The effect of SnO2 content on the sensitivity and selectivity to CO and CH4 were also investigated. The mechanistic aspect due to the enhancement of the sensitivity and selectivity of SnO2/MCM-41 gas sensors to H-2 is briefly discussed. (C) 1999 Elsevier Science S.A. All rights reserved.