Triethylamine Gas Sensing Properties Of Tungsten-based And Iron-based Oxide Semiconductors

Triethylamine is a kind of flammable and explosive raw material,which is very harmful to human skin,mucosa and nervous system.At present,the detection of trithylamine generally exists the problems such as slow response,poor selectivity and stability.Thus it is urgent to fabricate fast and strong anti-interference sensors to achieve accurate monitoring of triethylamine.Among the many types of sensors,the gas sensors based on metal oxide semiconductor attract the researchers attention because of their advantages of security,stability and long service life.The proportion of these sensors in the trithylamine sensors increases gradually.Therefore,it is particularly critical to research and optimize sensitive materials.When highly efficient sensitive materials are synthesized,the problems such as too slow triethylamine detection will be improved.In order to regulate the micro-nano structure of sensitive materials,and to prepare metal oxide semiconductor materials that can promote gas adsorption and facilitate electronic transmission,we have synthesized tungsten oxide hierarchical structure,iron oxide microspheres,ferrite and iron-based composite oxide with more adsorption sites,actives sites or diffusion mesopores,so as to achieve fast and stable detection of triethylamine.The characteristics of the above semiconductor materials are characterized,and the growth mechanism and gas sensitivity mechanism of triethylamine are also proposed.The main research contents are as follows:1.Hollow WO₃ microspheres assembled by interlock single crystal nanosheets are designed and prepared.The growth mechanism of microspheres is clarified by studying the micro-nano structure at different reaction times,including three steps of nucleation,spheronization and spheric cavitation.The response and recovery time of microspheres to 50 ppm triethylamine is as low as 1.5 and 22 s.The hollow structure provides more active sites for the attachment of triethylamine molecules and shortens the path of gas diffusion.The interlock structure reduces the energy loss across the grain barrier in electron transport.The microsphere sensor is a new type of trithylamine sensor which combines response and recovery speed,selectivity and stability.2.WO3 nanoclusters with single crystal nanorods arranged in order are designed and synthesized.The effects of reaction time and temperature on the morphology of the samples are discussed.The response of similar micro-nano structures to triethylamine is studied,and it is found that the nanoclusters have strong ability to detect triethylamine,with short response time?1.5 s/50 ppm?,low detection limit?500 ppb?and strong anti-interference ability.The response values of nanoclusters to triethylamine is 4.5 times that of trimethylamine,30 times that of aniline and 100times that of ethanol,formaldehyde,acetone and other gases.Nanocluster sensor is suitable for rapid detection of triethylamine in mixed gas environment.3.Mesoporous Fe₂O₃ microspheres are designed and prepared.The microspheres obtained by in situ decomposition of precursors have a large number of mesoporous deep in the sphere.The response and recovery time of the microsphere sensor to 50ppm triethylamine is?1 s and 2.5 s,and continuous and rapid detection can be realized for high concentration of triethylamine above 100 ppm,without significant resistance drift in the whole process.The microsphere sensor is suitable for ultra-fast detection of triethylamine in a single gas environment.4.Metal-Organic framework precursors with different micro/nano structures are designed and synthesized.The response of the precursor-derived NiFe2O4 polyhedron to 50 ppm triethylamine is 18.9 at 190°C.The low operating temperature of NiFe2O4polyhedron is due to the active introduction of a large number of oxygen vacancies.And the fast response time results from the polyhedron with hollow structure.The effects of specific surface area and oxygen vacancy ratio on the sensing performance of triethylamine are investigated.5.A porous ZnFe2O4/ZnO composite material derived from Prussian blue is successfully synthesized,and the growth mechanism of ZnFe₂O₄/ZnO is clarified.The ZnFe2O4/ZnO composite material with porous structure and heterojunction exhibit excellent triethylamine gas-sensing properties.The operating temperature is 170°C,and the response time to 100 ppm triethylamine is as low as 1 s.The sensor based on ZnFe2O4/ZnO composite material shows good stability and selectivity,and can ultra-fastly and continuously detect triethylamine at low operating temperature.The novel tungsten-based and iron-based oxide semiconductors with high face activities are synthesized,which not only improving the rate of triethylamine diffusion adsorption and decomposition,but also reducing the energy loss of when electron crossing grain boundaries to surface combined with physical adsorption oxygen in materials.The triethylamine sensors based on the above materials with great potential in the fields of agriculture,industry and daily life.