Electrospinning And Gas Sensing Properties Of Flexible ZnO/Carbon Fiber Composite Film

All kinds of poisonous and harmful gases,including nitrogen oxides,are constantly produced in industrial activities,and the gases in nitrogen oxides,except nitrogen dioxide,are extremely unstable.When exposed to light,humidity or heat,they become nitric oxide and nitrogen dioxide.The emission of these gases seriously endangers human health and living environment,so in the need of environmental monitoring and clinical diagnosis,various forms of gas sensors are constantly produced,one of the most important is semiconductor gas sensors.Thanks to the rise of wearable devices and the application of special scenes,the research of flexible gas sensors has become more and more popular.At the same time,high sensitivity and low detection limit are still valued.PAN-(CH3COO)2Zn / DMF solution and PAN-(CH3COO)2Zn / DMF solution doped with PMMA were electrospinned and carbonized to prepare flexible ZnO / carbon fiber composite membrane gas sensor and porous flexible ZnO / carbon fiber composite membrane gas sensor.The low concentration(2 ppm-50 ppm)NO2 gas was detected at room temperature using these two sensors.Morphology analysis,spectrum analysis and flexibility test were carried out for the composite film,and its gas sensing characteristics were compared.The specific research contents are as follows:The composite film of(CH3COO)2Zn / PAN nanofibers was obtained by electrospinning PAN-(CH3COO)2Zn / DMF solution.After preoxidation in air,it became ZnO / PAN nanofiber composite film,and then carbonized under the protection of nitrogen to ZnO / carbon fiber composite film.The morphology,structure and composition of the composite film were analyzed by SEM,EDS,XPS and FTIR.The results are as follows: the ZnO / carbon fiber composite film with a diameter of about 100 nm and a uniform distribution of 65% carbon content can be prepared by electrospinning and carbonization at 600 ? under nitrogen.During the heat treatment,the zinc acetate in the fiber continuously transforms into ZnO,The fiber diameter is decreasing.The results are as follows: the response of the composite membrane to 50 ppm NO2 at room temperature is 5%,and after 30 days of testing,the response has been kept at about 5% under 50 ppm NO2.The preparation process of ZnO / carbon fiber composite membrane is simple,and it has good response characteristics to low concentration of NO2 at room temperature.After spinning and carbonizing PAN-(CH3COO)2Zn / DMF solution doped with PMMA,ZnO / carbon fiber composite film with porous morphology was prepared,and then the corresponding detection was carried out.The results show that the porous ZnO / carbon fiber composite membrane has larger specific surface area,higher response to NO2 at room temperature,good selectivity and high stability.The flexibility test of the two composite membranes shows that the composite membrane has a certain degree of flexibility.It is hoped that the porous ZnO / carbon fiber composite membrane material can be used to produce a higher performance NO2 gas sensor which can be tested at room temperature.