Preparation Of One Dimensional Nanomaterials Of Metal Compound Oxide By Electrospinning And The Studies Of Their Gas Sensing Properties

In this thesis,the application,classification and properties of gas sensors were summarized in detail.Besides,several improvement methods of the semiconductor gas sensor were described.Furthermore,an overview of the one-dimensional material about its synthetic method and application on gas sensors were reviewed,and the application of electrospinning in synthesis of one-dimensional materials was introduced emphatically.Moreover,the formation and gas sensing properties and mechanisms of Zn₂Fe O₄,Cd₂SnO₄,BaSnO₃ and Ga₂O₃-SnO₂ nanomaterials were also studied.Herein,Zn₂FeO₄,Cd₂SnO₄,BaSnO₃ and Ga₂O₃-SnO₂ nanomaterials were obtained by the horizontal or vertical type electrospinning equipment,and the SEM,XRD,FT-IR,UV-Vis,XPS and TG-GSC were applied in characterizing these materials,which suggestting that calcination temperature has a certain effect on formation of materials.In addition,the gas sensing properties and mechanisms of these one-dimensional materials were investigated.The results showed that these materials have a potential application in gas sensors.The results of sensing properties are as follows:The sensors based on Zn Fe₂O₄ nanofibers obtained at 500^℃ for 2 h showed high response and gas sensing selectivity to acetone when operating at 190^℃.The detection limit could be down to 1 ppm（1.1）,the response times and recovery times for different concentrations of acetone were very short.The sensors based on Cd₂SnO₄ nanotubes prepared at 650^℃ for 10 h showed high response and gas sensing selectivity to acetic acid when operating at 190^℃.When the concentration of acetic acid lowed to 0.2 ppm,the sensitity was still able to reach 1.5.The sensors based on BaSnO₃ nanotubes nanotubes obtained at 700^℃ for 6 h showed high response and gas sensing selectivity to acetic acid when operating at 245^℃.The response to 1000 ppm acetone attained maximum value（96.8）,When the concentration of acetic acid lowed to 0.3 ppm,the sensitity was still able to reach 1.36.When the ratio of Ga₂O₃ reaches 60%,the sensors based on Ga₂O₃-SnO₂ composite nanotubes obtained at 650^℃ for 5 h showed the highest response and best selectivity to trimethylamine when operating at 25^℃,indicating the operating temperature is low.The response to 1000 ppm trimethylamine attained to 51,when the concentration of trimethylamine lowed to 0.8 ppm,the sensitity was still able to reach 1.3.