Construction And Gas Sensing Properties Of Porous Indium Tin Oxide Microspheres

In the context of the increasing energy problem and the rapid development of medical technology,gas sensors,as gas information collection devices,play an important role in monitoring air pollution,ensuring industrial production,and early diagnosis of diseases.As the main member of gas sensors,metal oxide semiconductor(MOS)gas sensors have many advantages,such as portability,low cost,small size,and easy integration.They have great research and development prospects.The core of metal oxide semiconductor gas sensors is nanoscale metal oxide gas sensing materials.The functions and application scenarios of gas sensors depend on the intrinsic properties of metal oxide gas sensing materials.Therefore,developing and improving metal oxide sensing materials and exploring the gas sensing mechanism and structure-activity relationship of metal oxide gas sensing materials have important research significance.In this thesis,based on the unique intrinsic properties of indium tin oxide(ITO)such as conductivity,suitable energy band structure,and ease of integration,porous indium tin oxide microspheres were successfully prepared by solvothermal method,and a gas sensor based on this material was fabricated.Its sensing performance was systematically investigated,and its gas sensing mechanism and structure-activity relationship were discussed and analyzed in depth.The specific research results are as follows:1.Porous indium tin oxide microspheres were prepared using indium tin alkoxide as precursor by solvothermal method.Gas sensitivity testing shows that it has excellent selectivity,extremely high sensitivity,and good stability,as well as extremely short response-recovery time(<3 s)and low operating temperature(200 ℃)for hydrogen.The structure-activity relationship analysis shows that the specific chemisorbed oxygens on the surface of indium tin oxide microspheres,the intrinsic high activity of tin dioxide,and the porous structure are the main reasons for their low operating temperature,fast response recovery speed,and high response value.2.Low content Pt modified porous indium tin oxide microspheres were prepared by a simple impregnation method,and the surface modified Pt existed in the form of Pt/Pt Ox.The gas sensitivity test indicates that Pt-II@ITO It has the advantages of high response value(S ≈ 20),high selectivity,high moisture resistance and high stability to acetone gas,and has the practical application prospect of detecting diabetes.Surface modified Pt not only has the catalytic effect of the traditional view,but also plays a key role in adjusting the electronic structure of materials and improving the content of chemisorbed oxygens on the surface.