Preparation Of Hollow ZnO/SnO₂/Zn₂SnO₄ Nanofibers And Amorphous ZnSnO₃ Microcubes And Their Gas Sensing Properties

After several decades of development,semiconductor metal oxide gas sensor has been rapidly developed by the efforts of a large number of researchers,but its low sensitivity,poor selectivity,and sensitivity to the environment are still important issues for researchers nowadays.In this paper,zinc tin oxide is the research object,aiming at the preparation of high-performance gas sensing materials,combined with the current development trend and research status of semiconductor sensors,further preparing gas-sensitive materials with good performance by adjusting process parameters,combined with physical chemistry.Characterization,performance testing and other means have further analyzed its gas sensing mechanism.The specific research content of this thesis mainly includes the following two parts:1.In this work,porous ZnO/SnO₂/Zn₂SnO₄,ZnO/SnO₂ and SnO₂/Zn₂SnO₄ composites nanofibers with hollow nanostructure via electrospinning method.The composites nanofibers were characterized by X-ray diffraction?XRD?,scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,and X-ray photoelectron spectroscopy?XPS?.The gas sensing properties of the as-synthesized samples were systematically studied.It was worth noting that compared with ZnO/SnO₂ and SnO₂/Zn₂SnO₄ composite nanofibers,the porous ZnO/SnO₂/Zn₂SnO₄ hollow nanofibers had excellent gas sensitivity to ethanol.For 200 ppm ethanol,the response could reach 97.39 at a relatively low working temperature of 225°C.Excellent gas sensitivity is attributed to the porous hollow structure and the heterojunction between the metal oxides ZnO,SnO₂ and Zn₂SnO₄.2.The pure and NiO sensitized monodisperse amorphous zinc tin oxide?a-ZTO?microcubes were synthesized via an in-situ precipitation method and subsequent wet impregnation.XPS results revealed that NiO sensitization increased the relative content of chemisorbed oxygen and oxygen vacancies on the surface of a-ZTO microcubes.Compared to pure a-ZTO microcubes,0.75 at%NiO sensitized a-ZTO microcubes can significantly improve the gas sensing performance to formaldehyde at 200°C,which may be attributed to its uniform morphology and modification of NiO on the surface of a-ZTO microcubes.Further,the gas sensing mechanism is briefly discussed.