Preparation And Gas Sensing Performance Of Metal Oxide Gas Sensing Materials

Semiconductor gas sensors, which have simple structure, low cost, high sensitivity and mature fabricating technique, are now widely employed in detection of toxic and inflammable gases and metering of atmospheric gases.The conventional semiconductor gas-sensing materials (SnO2, Fe2O3, ZnO, and so on,) have been extensively studied by many researchers, and the application of SnO2-based gas sensors has been developed in domestic and industrial fields. But the semiconductor gas sensors have some disadvantages such as poor sensitivity, high power consumption and large dependence of environmental temperature and humidity, and the sensing mechanism is not very clear, thus the development and application of semiconductor gas sensor are limited. To work out these problems, we have studied the preparation, sensitivity and sensing mechanism of new material, CoFe2O4 andZnIn2O4 .In this thesis, we have prepared CoFe2O4 and ZnIn2O4 with chemical coprecipitation method and studied their gas-sensing properties and resistance properties, we find that CoFe2O4 and ZnIn2O4 that have spinel structure not only have good gas-sensing properties, but also have better selectivity than simple oxide. Moreover, we study the dope of In2O3 , and study its gas-sensing properties and resistance properties.CoFe2O4 is sensitive to low concentration alcohol and acetone, for other gases it has not sensitivity, so this material may be used to inspect low concentration alcohol and acetone. Furthermore, for low concentration alcohol and acetone sensitivity and concentration have linearity, so this material is good sensitive material.ZnIn2O4 is sensitive to low concentration alcohol, acetone and H2, for other gases it has not sensitivity, moreover it can be used to inspect low concentration alcohol, acetone and H2.