Preparation And Characterization Of Graphene-based GAS Sensor

As a widely used kind of sensors, gas sensors play an important role in industrial production, environmental monitoring and other fields. At present, most gas sensors are prepared by mainly using inorganic oxide materials with such disadvantages as high working temperature, large volume, slow response, high power consumption, poor reproducibility and other defects. Discovered in 2004, graphene has become a hot spot to be researched by many scholars due to its unique physical, chemical and mechanical properties. Gas sensors based on graphene have such advantages as working at room temperature and fast recovery.To solve the problems above, reduced graphene oxide was chosen to prepare a series of gas sensors on the interdigital electrodes by air-brushing. The data acquisition system was used to record the responses of gas sensors to ammonia, carbon monoxide and nitrogen dioxide, and the sensing properties of the gas sensors were analyzed. In addition, reduced graphene oxide was combined with organic polymers(including poly-2-vinyl pyridine and polyaniline) to prepare composite film for improving the performance of gas sensors.The mainly work is as follows:(1) The RGO dispersion in different mass fraction was used to prepare sensitive film by air- brushing. The sensitive film was characterized by SEM(scanning electron microscope) and UV-vis. And The response to three target gases was studied It was found that the RGO film had a maximum sensitivity to ammonia, and it had a good reproducibility for ammonia and nitrogen dioxide, but both the response time and recovery time of all prepared sensors were very long.(2) The RGO sensitive films combined with P2 VP solution in different mass fraction were prepared by air- brushing. The sensitive films were characterized, and their responses to three target gases were tested. The RGO/P2 VP composite film had shorter response time and recovery time, and better repeatability and linearity than RGO film.(3) The RGO sensitive films combined with PANI solution in different mass fraction were prepared by air- brushing. The sensitive films were characterized, and their responses to three target gases were tested. Compared with RGO film, the RGO/PANI composite film had much higher sensitivity to ammonia and nitrogen dioxide, and its resistance change was different to the change trend of the RGO film. Compared with RGO/P2 VP composite film, the RGO/PANI composite film had shorter response time and recovery time. The RGO/PANI composite film had high reproducibility for ammonia and nitrogen dioxide and low reproducibility for carbon monoxide.