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

MCM-41 modified SnO2 (SnO2/MCM-41) gas sensors were prepared by mechanicall y mixing SnO2 with MCM-41 (which is a novel high-surface-area mesoporous ma terial) followed with thermal treatment in air at 700 degrees C. H-2, CO an d 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 (weig ht ratio) possessed the highest H-2 sensitivity. The sensitivities to CO an d CH4 were also found to be improved on the SnO2/MCM-41 sensors at much hig her temperature ranges. The effect of SnO2 content on the sensitivity and s electivity to CO and CH4 were also investigated. The mechanistic aspect due to the enhancement of the sensitivity and selectivity of SnO2/MCM-41 gas s ensors to H-2 is briefly discussed. (C) 1999 Elsevier Science S.A. All righ ts reserved.