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Preparation And Gas-sensing Properties Of Zn-Al Metal Oxide

Posted on:2013-03-02Degree:MasterType:Thesis
Country:ChinaCandidate:W L RuanFull Text:PDF
GTID:2231330395465576Subject:Chemical processes
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Gas sensor could detect many gases which are flammable, explosive, poisonous andinfectant. Sensors of metal oxide semiconductor are one kind of gas sensors and have a greatadvantages on sensitivity, responsing time and design of structure; Sensors of metal oxidesemiconductor have many advantages in actual application, such as easy use, small volumn,cheap cost and easy popularity. Although sensors of metal oxide semiconductor have so manyadvantages, single metal oxide has disadvantages on selectivity and stability. The study ofmaterial of metal oxide semiconductor is from single metal oxide, adulterating other metaloxide to composite metal oxide in order to improve the gas-sensing property of material andobtain the material of higher sensitivity, higher selectivity and longer stability.In this paper, it mainly discusses the preparation, structure and morphology and theirgas-sensing property of two Zn-Al metal oxides. They are Crystal ZnO-noncrystal Al2O3andZn-Al HTlc (0.1mol Fe).This paper includes two aspects:1. Preparation and structure and morphology of crystal ZnO-noncrystal Al2O3and theirgas-sensing propertyCrystal ZnO-noncrystal Al2O3is prepared by annealing Zn-Al HTlc. The morphologyand structure of crystal ZnO-noncrystal Al2O3are characterized by field emission scanningelectron microscopy, energy dispersive spectrometer, X-ray diffraction, BET surface area andpore distribution analysis and thermogravimetric analysis. The average crystalZnO-noncrystal Al2O3crystallite size is about15.68nm. The crystal ZnO-noncrystal Al2O3exhibits a good response to some organic gases, such as ethanol and n-butanol. The sensorresponses to350ppm ethanol and n-butanol are112.12and167.18, respectively, at a workingtemperature of290℃. In addition, the sensor exhibits a good response to methanol,2-propanol, acetone and dimethylbenzene. The relationship between the gas-sensingproperties and the microstructure of crystal ZnO-noncrystal Al2O3is also investigated.2. Preparation and structure and morphology of ZnO-Al2O3-FeO and their gas-sensingpropertyZnO-Al2O3-FeO is prepared by annealing Zn-Al HTlc. The morphology and structure of ZnO-Al2O3-FeO are characterized by field emission scanning electron microscopy, energydispersive spectrometer, X-ray diffraction, BET surface area and pore distribution analysisand thermogravimetric analysis. The average ZnO-Al2O3-FeO crystallite size is about28.31nm. The ZnO-Al2O3-FeO exhibits a good response to some organic gases, such as ethanol andn-butanol. The sensor responses to200ppm ethanol and133.33ppm n-butanol are32.30and44.24, respectively, at a working temperature of290℃. In addition, the sensor exhibits agood response to methanol,2-propanol, acetone and dimethylbenzene.
Keywords/Search Tags:Zn-Al metal oxides, gas sensor, crystal ZnO-noncrystal Al2O3, ZnO-Al2O3-FeO, gas-sensing property
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