| Metal oxide nanomaterials have excellent gas-sensitive properties and can be used as gas-sensitive materials of sensors.This article mainly studied Sn,Ga and In metal oxide in?and?group.And indium oxide,tin oxide and gallium oxide nanomaterials with different morphologies were prepared by various techniques.Their sensitive properties were explored.At the same time,in order to further improve the gas sensitive performance of the products,their physical structure and surface morphology were regulated by fiber ordered arrangement,doping,surface modification and so on.The sensitivities were significantly improved.The main conclusions are as follows:(1)Using electrospinning method combined with heat treatment,a preparation process of hollow indium oxide fiber was explored.It was found that in the heat treatment process,the formation of hollow fiber structure at high temperature could be achieved by adopting a faster heating rate,and then the hollow structure could be maintained by using a slower cooling rate.(2)The ordered indium oxide hollow nanofibers can be obtained by using the frame collector.It was found that the sensitivity of the ordered fiber to ethanol of100ppm reached 29.4 at the optimum operating temperature.Compared with the irregular indium oxide nanoparticles prepared by sintering method,the gas sensitivity of the ordered fiber to ethanol was more than doubled.The indium oxide hollow fibers were doped with La element and arranged in order,it was found that when the atomic ratio of In to La element is 100:7,the sensitive performance of the corresponding sample is improved most obviously.Its sensitivity to ethanol of 100ppm can reach 32.8.(3)The La doped ordered Sn O2 nanofibers were prepared by electrospinning combined with a double-ring collector method and its sensitivity to ethanol of 100 ppm reached 241 at the optimal operating temperature.Compared with the disordered Sn O2fibers,the sensitivity was improved by 20%-40%on average.In addition,through a physical model,the main factors affecting the spinning length were analyzed,and the empirical formula was given.(4)Gallium oxide nanomaterials were prepared by electrospinning method and sintering method,respectively.It was found that gallium oxide nanoribbon could be obtained by electrospinning method.The material was hard in texture,but had poor gas sensitivity to ammonia and high working temperature.The gallium oxide nanoparticles prepared by sintering method can obtain good gas sensitivity at room temperature after surface modification.When the molar ratio of Ga2O3 to aniline monomer(C6H7N)is100:20,the sensitivity of the sample to ammonia of 100ppm concentration can reach15.4,which is 7 times higher than that of the modified nanoparticles. |
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