Study Of The Preparation And Sensitive Properties Of LaFeO₃,PrFeO₃ Nanofibers By Electrospinning

Nowadays,with the rapid development of industrialization,and the improvement of science and technology,people's consumption of earth resources is increasing day by day.At the same time,various environmental issues have also erupted.Various kinds of explosive,flammable,poisonous and harmful gases generated in industrial production and daily life are discharged into the atmosphere at all times,such as nitrogen oxides,sulfur oxides,and carbon monoxide.These gases not only have a great impact on the production and living environment,but also pose a threat to the safety of human life and property.Therefore,real-time monitoring of toxic and hazardous gases in the surrounding environment and alarm protection has become a subject that humans have to face and study.At present,the detection methods for harmful gases mainly include electrochemical methods,gas chromatography,and optical methods.However,due to the high cost of these methods and the complexity of the device,they cannot be effectively used in real life.Gas sensors,which can convert the type and concentration of gases to be measured into electrical signals,have been widely used in chemical and chemical industries,protective alarms and air detection industries owing to low production cost,high response value and good stability.However,gas sensors still have problems including high operating temperature,long response recovery time,and lack of selectivity need to be improved at this stage.Choosing the appropriate matrix material and doing reasonable optimization is the core of solving these problems.Perovskite?ABO₃,octahedral structure?has been widely used in solar cells,giant magnetic effects,photocatalysis,and high temperature resistance,especially perovskite rare earth oxides.In this paper,LaFeO₃ nanofibers and PrFeO₃ nanotubes were successfully prepared by electrospinning method.Moreover,the gas sensitivity of the samples was tested and the reasonable reaction mechanism was proposed based on the experimental results.The main research is as follows:1.LaFeO₃ nanofibers doped with different cobalt contents were successfully prepared by an electrospinning and followed calcination process.The structure and morphology of the samples were characterized by XRD,SEM,TEM,EDX and BET,and the results indicate that all the samples were roughness and uniform in size.Compared with pure LaFeO₃ nanofibers,the Co-doped LaFeO₃samples was better in dispersity and larger in specific surface area.The gas sensitivity test results demonstrate that the LaFeO₃ nanofibers with 3wt%Co doping have the best gas-sensing performance,and the response to 500 ppm glacial acetic acid is as high as 435 at a temperature of130?.2.By annealing the precursor obtained in electrospinning process at a high temperature,the porous PrFeO₃ hollow nanofibers with roughness surface were obtained.The average diameter of the hollow nanofibers is about 135 nm,and the tube-wall is about 35 nm.Gas sensor based on PrFeO₃nanofibers exhibits excellent selectivity to acetone at an optimal operating temperature of 180?,and the response is 141 toward to 200 ppm acetone,which is 50 times the benzene gas response?².8?.The response and recovery time are also as low as 5 s and 6 s,respectively.The results show that the as-prepared PrFeO₃ nanofibers have good selectivity,high response values and fast response recovery time for acetone.In addition,the possible formation mechanism and gas sensitivity mechanism of PrFeO₃ hollow nanofibers are also proposed.