The Effect of Zeolite Composition and Grain Size on Gas Sensing Properties of SnO(2)/Zeolite Sensor

In order to improve the sensing properties of tin dioxide gas sensor, four kinds of different SiO(2)/Al(2)O(3) ratio, different particle size of MFI type zeolites (ZSM-5) were coated on the SnO(2) to prepared zeolite modified gas sensors, and the gas sensing properties were tested. The measurement results showed that the response values of ZSM-5 zeolite (SiO(2)/Al(2)O(3) = 70, grain size 300 nm) coated SnO(2) gas sensors to formaldehyde vapor were increased, and the response to acetone decreased compared with that of SnO(2) gas sensor, indicating an improved selectivity property. The other three ZSM-5 zeolites with SiO(2)/Al(2)O(3) 70, 150 and 470, respectively, and grain sizes all around 1 μm coated SnO(2) sensors did not show much difference with SnO(2) sensor for the response properties to both formaldehyde and acetone. The sensing mechanism of ZSM-5 modified sensors was briefly analyzed.