Construction Of Porous SnO₂ Matrix Composite And Study Of Its Gas Sensitive Properties

In this thesis,disordered porous tin dioxide material was prepared by sol-gel hard template method.The material was tetragonal rutile structure.The morphology of the material was cluster structure,and the clusters were constituted of particles.When the concentration of NO_x gas was 100 ppm,the sensitivity reached a maximum value of 54%,and the response time was only 19.5 s,the detection limit of the sensor was 5 ppm at the room temperature.A chemical deposition method was used to prepare disordered porous CuO/SnO₂composite material,the CuO/SnO₂ was a p-p combined structure semiconductor,a layer of CuO thin film was formed on the surface of disordered porous SnO₂ matrix material.When the NO_x concentration was 100 ppm,the response reached 74%,and the response time was only 7.0 s,and the detection limit was 1 ppm at the room temperature.The excellent restorability and superior selectivity to NO_x could be observed in the prepared sensor.In2O3 sensitized disordered porous In2O3/SnO2 composite material was prepared by a sol-gel hard template method.When the doped concentration of In2O3 was 0.1%,the composites exhibited the highest sensitivity and selectivity.The particles diameters of the material were 20-30 nm.When the NOx concentration was 100 ppm,the response reached80.3%,the response time was only 2.0 s,and the detection limit to NO_x gas was only 0.08ppm at the room temperature.An Electro-deposition method was used to prepare disordered porous Cr2O3/SnO2composite material,the Cr2O3/SnO2 composite was a p-p combined structure semiconductor,a layer of Cr2O3 thin film was formed on the surface of disordered porous SnO2 matrix material.When the NOx concentration was 100 ppm,the response reached 71%,the response time was only 2.5 s,and the detection limit to NOx gas was 0.3 ppm at the room temperature.The excellent restorability and superior selectivity could be observed in the prepared sensor.