Study On The Preparation Of SnO₂-Based Nanocomposites By Electrospinning And Their Gas Sensitivity

As one of the most promising gas sensitive materials,SnO₂ has the advantages of low cost and good stability.The nanocrystalline SnO₂ exhibits many unique properties in optical,electrical,thermal and magnetic fields due to the changes in its crystal structure and surface electronic state.In this paper,using the spinning method,we explore the ways to enhance the gas sensitivity of the SnO₂ materials from the aspects of doping or controlling the morphology.Three kinds of SnO₂-based nanocomposites have been synthesized and made into gas sensors to test their gas-sensing properties.The following are the main conclusions:1.La-doped SnO₂-based nanofibers were prepared by electrospinning and used as gas sensors.The experimental results show that the gas-sensitive material has high sensitivity,good stability and lower operating temperature.In an atmosphere of 500 ppm ethanol and ammonia,the sensitivity of La-doped SnO₂-based gas sensors is about 420 and 480,respectively.Compared with pure SnO₂ fibers,the gas sensitivity characteristics are significantly improved.2.Orderly La-doped SnO₂-based nanofibers were prepared by improving the collection method of spinning.The experimental results show that this gas-sensitive material has improved sensitivity,stability and response time for ethanol and ammonia.Compared with disordered La-doped SnO₂-based composite nanofibers,its gas sensitivity is improved about 10%.3.In-doped SnO₂-based nanofibers were prepared by electrospinning.The experimental results show that the gas-sensitive material has better stability and selectivity,as well as a shorter response time.In an atmosphere of 500 ppm ethanol and ammonia,the sensitivity of In-doped SnO₂-based gas sensor was 415 and 105 at the optimum temperature,respectively.The role of La and In is not the same in improving the gas-sensitive properties of the material.The former helps to increase sensitivity and the latter helps improve responsiveness.