Study On The Detection Performance Of Nano-ZnFe₂O₄ Through Flame Aerosol Synthesis For The Concentration Of Flammable Liquids Vapor

Volatile and flammable liquids have been widely used as liquid chemical materials in many fields,mainly including coal chemical industry,petrochemical industry,fuel coating manufacturing,etc.During the process of production,storage and processing,serious safety accidents may be caused due to leaks and other reasons,such as poisoning,fire and explosion.Therefore,how to achieve the safety detection of the concentration of these volatile and flammable liquids remains to be further studied.Metal oxide semiconductor gas sensors have become a research hotspot of gas sensors due to their low cost,simple operation,and a wide variety of detectable gases.However,it has the disadvantages of poor selectivity and insufficient sensitivity in the actual application process,studies have found that nano-structuring has great potential in improving the gas sensitivity of materials and promoting the miniaturization of gas sensors.Therefore,this paper adopts the premixed stagnation flame synthesis to prepare nano-Zn Fe₂O₄.To explore the best precursor ratio and experimental conditions in the preparation of Zn Fe₂O₄by flame synthesis through a large number of experiments,and improve the sensitivity of the multi-metal oxide gas sensor from the perspective of the material's microscopic morphology and rich defect states,such as response recovery speed,selectivity,sensitivity,etc.It provides experimental basis for the subsequent safety detection of volatile and flammable liquids by gas sensors.The conclusions of this paper are as follows:(1)The premixed stagnation flame synthesis method can successfully prepare Zn Fe₂O₄spherical nanoparticles.Compared with conventional chemical synthesis,the phase purity of Zn Fe₂O₄is higher and the morphology is more uniform.The particle size of spherical particles is about 400?500nm,which are assembled by a large number of nanoparticles with a particle size of about 10nm.(2)The third processing condition is determined as the optimum experimental condition,as the equivalence ratio of O₂/C₂H₄was 5.44 and N₂was 9.82 SLPM.The surface of Zn Fe₂O₄spherical nanomaterials has extremely high oxidation characteristics and the crystal structure is polycrystalline,with a specific surface area of 23m²/g and a large number of pores around 4.5nm.(3)The gas sensitivity test results show that the flame synthesized Zn Fe₂O₄spherical assembled nanomaterials are responsive to volatile and flammable liquids such as acetone,ethanol,ethylene glycol and methanol,and it has good selectivity and sensitivity especially for acetone,and the best operating temperature for acetone is 225?.The response of flame synthesis and chemically synthesized Zn Fe₂O₄nanomaterials to 100ppm acetone vapor reached 26/7,respectively,and the response recovery time was stable at 14s/8s and 33s/20s during the cycle test.The gas sensor prepared by flame synthesis has good stability,and the responsiveness of Zn Fe₂O₄gas sensor can still reach 92%of the original after 30 days.