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  本文選題：氣體傳感器 + p-Co_3O_4/n-SnO_2�。� 參考：《西南交通大學(xué)》2017年碩士論文

【摘要】：近年來,隨著人民生活水平的提高以及對環(huán)保的日益重視,人們對各種有毒、有害氣體的檢測提出了更高的要求�；�于金屬氧化物的半導(dǎo)體型氣體傳感器因具有較低的成本和優(yōu)異的氣敏特性成為氣體傳感器領(lǐng)域的研究熱點。氣體傳感器的氣敏性能取決于傳感材料的結(jié)構(gòu)特性。因此制備高性能氣敏材料一直是半導(dǎo)體氣體傳感器的研究重點和難點。本論文以合成出高性能的氣敏材料為研究目標(biāo),通過調(diào)控氣敏材料的形貌結(jié)構(gòu)來對其氣敏性能進行了研究。主要研究內(nèi)容如下:(1)利用p-n異質(zhì)結(jié)的界面協(xié)同效應(yīng)來調(diào)節(jié)氣敏材料的氣敏選擇性。本文首先采用操作簡單的浸泡煅燒法制備了不同Co/Sn摩爾比的p-Co_3O_4/n-SnO_2 p-n異質(zhì)結(jié)復(fù)合材料,并對其氣敏性能進行了系統(tǒng)研究。實驗結(jié)果表明,該p-Co_3O_4/n-SnO_2復(fù)合氣敏材料對典型還原氣體如CO,H_2S和NH_3顯示為n型氣敏響應(yīng),對H_2則表現(xiàn)出獨特的p型響應(yīng)。我們將該獨特的氣敏響應(yīng)反轉(zhuǎn)行為歸結(jié)于p-Co_3O_4/n-SnO_2異質(zhì)結(jié)中SnO_2和Co_3O_4對還原氣體具有不同的氣敏反應(yīng)活性而導(dǎo)致的勢壘高度調(diào)制有關(guān)。該研究工作證明,利用異質(zhì)結(jié)材料對目標(biāo)氣體的不對稱氣體反應(yīng)活性可以實現(xiàn)調(diào)節(jié)p-n異質(zhì)結(jié)勢壘高度的調(diào)節(jié),為復(fù)合氣敏材料氣敏特性的優(yōu)化提供了重要的理論支撐。(2)研究了不同形貌Ag_3PO_4納米材料的室溫NH_3氣敏性能。目前關(guān)于Ag_3PO_4作為光催化劑的相關(guān)報道較多,而對將其作為氣敏材料用于氣體檢測還鮮有報道。我們利用離子交換法和固相研磨法制備出了納米管和納米顆粒兩種不同形貌Ag_3PO_4納米材料,并研究了形貌對其NH_3室溫氣敏性能的影響。氣敏性能測試結(jié)果表明,相較于Ag_3PO_4納米顆粒,Ag_3PO_4納米管具有更加優(yōu)異的氣敏特性,在室溫下對NH_3具有更高的靈敏度和選擇性,檢測限可低至1Oppm。該工作對研究Ag_3PO_4的室溫氣敏機理以及形貌對其氣敏反應(yīng)活性的影響規(guī)律奠定了基礎(chǔ)。
[Abstract]:In recent years, with the improvement of people's living standards and the increasing attention to environmental protection, people put forward higher requirements for the detection of various toxic and harmful gases. Semiconductor gas sensor based on metal oxide has become a research hotspot in the field of gas sensor because of its low cost and excellent gas sensitivity. The gas sensing performance of the gas sensor depends on the structure of the sensing material. Therefore, the preparation of high-performance gas-sensitive materials has been the focus and difficulty of semiconductor gas sensors. The aim of this thesis is to synthesize high performance gas sensing materials and to study their gas sensing properties by adjusting the morphology and structure of the gas sensing materials. The main contents of this study are as follows: (1) the gas sensing selectivity of gas sensing materials is regulated by the interface synergy of p-n heterojunction. In this paper, p-Co_3O_4/n-SnO_2 p-n heterojunction composites with different Co/Sn molar ratios were prepared by a simple soaking and calcination method, and their gas-sensing properties were systematically studied. The experimental results show that the p-Co_3O_4/n-SnO_2 composite gas sensing material exhibits n-type gas sensing response to typical reductive gases such as COG / H _ 2S and NH_3, and a unique p-type response to H _ (2). We attribute this unique gas sensing response inversion behavior to the barrier height modulation of SnO_2 and Co_3O_4 in p-Co_3O_4/n-SnO_2 heterostructures due to their different gas-sensing reactivity to reducing gases. It is proved that the potential barrier height of p-n heterojunction can be adjusted by using the asymmetric gas reaction activity of the heterojunction material to the target gas. It provides an important theoretical support for the optimization of gas-sensing properties of composite gas-sensing materials. (2) the room-temperature NH_3 gas-sensing properties of Ag_3PO_4 nanomaterials with different morphologies are studied. At present, there are many reports about Ag_3PO_4 as photocatalyst, but there are few reports that Ag_3PO_4 is used as gas sensing material for gas detection. Two kinds of Ag_3PO_4 nanomaterials with different morphologies were prepared by ion exchange method and solid phase grinding method. The effect of morphology on the gas sensing properties of NH_3 at room temperature was studied. The results of gas sensitivity test showed that compared with Ag_3PO_4 nanoparticles, the gas sensing properties of the nanotubes were higher than those of Ag_3PO_4 nanoparticles. The sensitivity and selectivity of NH_3 were higher at room temperature, and the detection limit could be as low as 1 Oppm. This work laid a foundation for studying the mechanism of Ag_3PO_4 gas sensing at room temperature and the effect of morphology on its gas sensing reaction activity.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TP212

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本文編號：1971694