Preparation,Characterization And Gas Sensing Properties Of SnO₂ Nanomaterials

Because nanomaterials have smaller particle size and larger specific surface area than traditional materials,nanomaterials have strange or abnormal physical and chemical properties that traditional materials do not have.Therefore,nanomaterials have been widely used in biomedicine,fine chemical engineering,gas sensing and other fields,so they have attracted more and more attention.SnO₂ nanomaterials have optical,electrical,magnetic,gas sensitive,electrochemical luminescence and other characteristics different from traditional materials.Therefore,they are widely used in photoelectric materials,catalysts,sensors and other aspects.However,among many gas sensors,triethylamine?TEA?gas sensor is rarely reported.The research contents of this paper mainly include three aspects.First,we successfully prepared a large number of SnO₂ nanowires/spot-modified SnO₂ microrods on SiO₂?300nm?/Si wafers by sputtering Au films by thermal evaporation method,and performed detailed morphology and structure characterization of the prepared samples;Second,we performed a systematic gas-sensitivity test on SnO₂ nanowires/spot-modified SnO₂ microrod samples with good morphology.Third,we simply analyzed the growth mechanism and gas content of SnO₂nanowires/spot modified SnO₂ microrod Responsive sensing mechanism.The main content is shown below.1.A magnetron sputtering method is used to deposit an Au film with a thickness of about3.5 nm on the SiO₂?300 nm?/Si wafer,and use this as the substrate.A large number of SnO₂nanowires were successfully prepared by using Sn powder as the source material at different preparation temperatures?900,950,1000 and 1050??,at different preparation times?20,40,60and 80min?and at different carrier gas flows?40,60,80 and 100sccm?.X-ray diffraction?XRD?,Raman spectroscopy?Raman?,scanning electron microscope?SEM?,energy scattering X-ray spectroscopy?EDS?,transmission electron microscope?TEM?,and selected area electron diffraction?SAED?Characterization,the optimal preparation conditions?1000?,60 sccm,20min?were obtained,and the growth mechanism of the prepared samples was discussed.A series of gas sensitivity tests were conducted on the samples prepared under the optimal preparation conditions,and it was concluded that the SnO₂ nanowire gas sensor had a lower detection limit for TEA gas,an optimal test temperature of 200?,a faster response/recovery time,and a better gas stability and selectivity.We also discuss the gas sensitivity mechanism based on SnO₂nanowire gas sensor.2.According to the mechanism of gas sensing,gas sensing is related to the material surface,that is,the rougher the surface,the larger the specific surface area,the better the performance of the gas sensor.Therefore,we try to improve the surface of the prepared material by using the same preparation method and different source materials.Sn and SnO?3,4,5,6:1?were used as source materials to successfully prepare a large number of SnO₂ micron rod modified with nanometer points on the SiO₂?300nm?/Si substrate of sputtering Au films by thermal evaporation.The morphology and structure of the samples were characterized by XRD,Raman,SEM and EDS,and the growth mechanism of the samples was discussed.Since Sn and SnO?5:1?and Sn and SnO?4:1?were used as source materials to prepare nanometer point modified SnO2micron bars with relatively large quantities and obvious surface point particles,the samples prepared by Sn and SnO?5:1?and Sn and SnO?4:1?were subjected to detailed gas sensitivity tests.It is concluded that SnO₂ micron rod gas sensor based on nanometer dot modification has lower detection limit of TEA gas,higher response of TEA gas and better gas selectivity than SnO₂ nanowire gas sensor.Thus,it can be concluded that the better the surface roughness of nanomaterials,the better the gas sensing performance.We also briefly analyze the sensing mechanism of SnO₂ micron rod gas sensor based on nanometer point modification.