Controllable Synthesis Of Zinc-tin Composites With Different Morphologies And Their Gas Sensing Properties

People are in contact with the gas at all times in life,different types of gas with different chemical properties,so the impacts on the human body are different.However,many gases are difficult to detect and easy to spread,which caused a great threat to the human life and property.Thus,the accurate detection of gas and harmful prevention is of great importance to gas sensor.Among the various types of gas sensors,metal oxide semiconductor gas-sensing materials are widely used in gas sensors,due to their low energy consumption,rapid detection,good stability and easy integration.Zinc-tin composites are one of the most widely studied materials for gas-sensing materials.In the detection of some special gases,zinc-tin composites have excellent properties such as formaldehyde,ethanol,hydrogen sulfide and other gases.In this paper,the influence of the morphology and composition of the materials on the gas sensing characteristics of ternary composite oxide zinc-tin materials is studied under the background of many sensitive materials.By optimizing the material morphology and the molar ratio of the elements to achieve the optimization of material properties,to promote the composite material meet the needs of high-performance gas sensor.In general,the relationship between the composition and morphology of zinc-tin composites and the gas-sensing properties was studied from the following three aspects:?1?Synthesis of octahedral,classification of octahedral,spherical Zn₂SnO₄/SnO₂composites.The Zn₂SnO₄/SnO₂ composites were synthesized by the coprecipitation method and subsequent high temperature calcination.The test results show that Zn₂SnO₄/SnO₂ has excellent gas-sensing properties for formaldehyde.Among the three morphologies,the performance of the classification of octahedral composites is the best.The SEM,BET and DRS of Zn₂SnO₄/SnO₂ were characterized.The best gas-sensing properties of the octahedral zinc-tin composites were attributed to the multi-layered structure of the surface,the largest specific surface area and the low Band gap width.At the same time,the gas sensor of the composite material has low detection limit,high sensitivity and good stability to formaldehyde gas.?2?Synthesis of hollow cube structure for ZnSnO₃ composites.A hollow cube with good morphology and uniform size was synthesized by one step method.The TEM and SEM study show that the synthesized white powder is a hollow cube with regular morphology.X-ray diffraction analysis concluded that ZnSnO₃ material is an amorphous composite.Among the ethanol,methanol,acetone,toluene,ammonia and hydrogen,ZnSnO₃ material has the best gas sensitivity to ethanol,and the stability of the sensor is excellent.Its excellent gas-sensitive properties are derived from the uniformity and structural stability of the hollow structure.?3?On the basis of the preparation of hollow structure ZnSnO₃,the composite materials with different zinc-tin ratios were obtained by the gradual slow etching of dilute hydrochloric acid.Due to the different solubility of zinc oxide and tin oxide in dilute hydrochloric acid,ZnSnO₃ hollow cube were slowly etched by 1M HCl.The results of EDX analysis show that the zinc-tin composites with different zinc-tin ratios have been successfully synthesized.The gas sensing properties of formaldehyde and ethanol were studied.It was found that the gas sensitivity of the composites to ethanol will increase with the presence of low content of Zn.When the amount of Zn was medium,the gas sensitivity of he composite material to formaldehyde will increase.A comparative study concluded that the composition of the material affects the selectivity of the material.In this experiment,the in-situ etching is used to control the composition of the material without changing the appearance of the material,thus ensuring the stability of the hollow structure and stability of the materials.Therefore,it provided a solution for the modification of multiple composite materials from the experimental methods and conclusions.