Fabrication Of Nano-modified Graphene-based Gas Sensor And Its Sensing Properties Toward Noxious Gases

Gas detection plays an important role in various fields of atmospheric monitoring,industrial production,daily life and submarine or automobile enclosed environment.Graphene gas sensors based on nanomaterials,such as SnO₂-reduced graphene oxide?SnO₂-RGO?and reduced graphenen oxide?RGO?,open up a new way to develop new gas sensors.It has congenital advantages like fast response,high sensitivity,low power consumption,good stability andso on.In order to relize a highly sensitive and rapid responding gas sensor,in this thesis,SnO₂-RGO and CuO-RGO films are deposited onto self-designed elctrodes via researching the film fabrication methods,and their gas sensing properties are investigated and discussed.Graphene and its nanocomposites are prepared based on drop-casting method,hydrothermal method,layer-by-layer?LbL?self-assembly method and thermal reducing method,and by using SEM,XRD and other analysis,the surface morphology and microstructure of the nano films are observed.In this paper,gas sensors are fabricated based on four kinds of films,including drop-casting RGO film,hrdrothermal SnO₂-RGO film,LbL-based SnO₂-RGO and CuO-RGO films.Ammonia,acetone and formaldehyde gases were selected to test the properties,the gas sensing properties of the film sensors are investigated at room temperature,consisting of sensitivity,response-recovery features,repeatability and stability characteristics.The testing results reveal the sensitive relationship between electrical characteristics of the film senors and different gases.The response characteristics of films that measured with mixed gas were discussed,and the mixed gas response models were created,too.In this thesis,the sensor array are fabricated by using the three nanocomposites films that the above mentioned for detecting the concentrations of the mixed gas,and the BP neural network is introduced to process the data gathered from sensor array for predicting the gas concentration.This paper focused on research the minitype,high sensitivity,low cost,high performance and low-temperature frendly gas sensors,which provides an experimental and theoretical basis for the protection of industrial.And futher more,it is the foundation for studying the sensor array.It is of great significance for envirnoment monitoring,industrial production,daily life and public security.