本文選題：生物模板 + 秸稈��； 參考：《吉林大學(xué)》2017年碩士論文

【摘要】：面對環(huán)境污染治理、工業(yè)生產(chǎn)安全以及日常生活健康等多方面的需求,開發(fā)出靈敏度高、響應(yīng)速度快、穩(wěn)定性高的氣體傳感器是目前亟須解決的問題。在各類傳感器中,金屬氧化物氣體傳感器由于成本低廉、工藝靈活性大、使用方法簡單、可探測氣體種類多等優(yōu)點(diǎn)引起廣泛關(guān)注。近年來,利用生物模板法合成多級精細(xì)復(fù)雜結(jié)構(gòu)的新型功能材料是新興研究方向。因此,選擇獲取簡單、數(shù)量龐大和綠色環(huán)保的生物模板制備金屬氧化物半導(dǎo)體氣敏傳感器具有重要的研究價值。本研究利用玉米秸稈的天然分級多孔結(jié)構(gòu),采用液相浸漬、焙燒的工藝,成功制備得到秸稈分級結(jié)構(gòu)ZnO材料,并對材料進(jìn)行物相組成、形貌結(jié)構(gòu)以及孔結(jié)構(gòu)分析,并研究了其氣敏性能,分析了秸稈分級多孔結(jié)構(gòu)對ZnO氣敏性能的影響。在秸稈分級結(jié)構(gòu)ZnO的基礎(chǔ)上,利用過渡金屬離子摻雜改性手段改善ZnO氣敏性能,為分級多孔結(jié)構(gòu)材料的組分優(yōu)化方面提供依據(jù)。本研究主要結(jié)果如下:(1)采用玉米秸稈為模板,經(jīng)過原料氨水抽提預(yù)處理、二次浸漬、焙燒去模板等工序,成功制備得到具有秸稈分級多孔結(jié)構(gòu)的ZnO材料。對樣品進(jìn)行表征,ZnO材料很好地復(fù)制保留了秸稈的分級多孔結(jié)構(gòu),而且其分級結(jié)構(gòu)是由大約50nm的納米顆粒構(gòu)成的。該樣品同時具有分級大孔和不對稱的細(xì)長介孔,樣品比表面積為32.84 m2/g,平均孔徑為18.9 nm,孔容為0.16 m3/g。(2)氣敏測試發(fā)現(xiàn),秸稈分級結(jié)構(gòu)ZnO對丙酮的靈敏度比常規(guī)ZnO高,但其最佳工作溫度也高于常規(guī)ZnO,這可能是因為秸稈分級結(jié)構(gòu)ZnO材料的表面活性不足,需要高的工作溫度也就是更高的表面反應(yīng)激活能才可以發(fā)揮其氣敏性能。秸稈分級結(jié)構(gòu)ZnO在340℃最佳工作溫度下對100 ppm丙酮的靈敏度可達(dá)~24,響應(yīng)和恢復(fù)時間分別為12 s和6 s。秸稈分級多孔ZnO的特殊結(jié)構(gòu)在不同尺度上為氣體在材料內(nèi)部快速擴(kuò)散傳輸提供了大量的通道,而且不論在微米尺度上還是納米尺度上均具有大的比表面積,這將為表面反應(yīng)提供更多的活性位點(diǎn),從而增強(qiáng)材料的氣敏性能。(3)采用過渡金屬離子摻雜及秸稈分級多孔ZnO的結(jié)構(gòu)優(yōu)勢相結(jié)合的方法,選用Ni作摻雜劑,制備得到了具有秸稈分級多孔結(jié)構(gòu)的Ni摻雜ZnO材料,大大改善了ZnO的氣敏性能。在340℃工作溫度下,ZnO:Ni元件對100 ppm丙酮的靈敏度可達(dá)~68,響應(yīng)和恢復(fù)時間分別僅為6 s和2 s,理論檢測限為116 ppb,該元件具有好的選擇性及長期穩(wěn)定性。氣敏性能優(yōu)于純ZnO可能是因為Ni摻雜ZnO材料相較于純ZnO具有更高的施主缺陷含量。
[Abstract]:Facing the demands of environmental pollution control, industrial production safety and daily life health, it is urgent to develop gas sensors with high sensitivity, fast response and high stability.In recent years, it is a new research direction to synthesize new functional materials with multilevel fine and complex structure by biological template method.Therefore, the preparation of metal oxide semiconductor gas sensors with simple, large number and green biological templates has important research value.In this study, the natural porous structure of corn straw was used to prepare the ZnO material by liquid phase impregnation and roasting, and the phase composition, morphology and pore structure of the material were analyzed.The gas sensing properties of ZnO were studied, and the effect of porous structure of straw classification on gas sensing performance of ZnO was analyzed.On the basis of ZnO of straw grading structure, the gas sensing properties of ZnO were improved by using transition metal ion doping modification method, which provided the basis for the composition optimization of graded porous structure materials.The main results are as follows: (1) using corn straw as template, ZnO material with straw grading porous structure was successfully prepared by pretreatment with ammonia water extraction, secondary impregnation, roasting and deformation.The sample was characterized by 50nm, which was made up of about 50nm nanoparticles, and retained the porous structure of the straw.However, the optimum operating temperature is also higher than that of conventional ZnO, which may be due to the lack of surface activity of straw fractionated ZnO, which requires a higher working temperature, that is, a higher surface reaction activation energy to give full play to its gas-sensing properties.The sensitivity of straw grading structure ZnO to 100 ppm acetone at 340 鈩，

本文編號：1739548