本文選題：氧化鎳 + Cr摻雜��； 參考：《吉林大學》2015年碩士論文

【摘要】：如今，科技高速發(fā)展，人們的生活水平快速提高的同時，各種各樣的問題越來越被人們所關注。其中空氣污染問題越來越嚴重，易燃易爆氣體和有毒有害氣體無時不刻地危害著人們的身體健康。因此，如何有效地監(jiān)測和檢測環(huán)境中易燃易爆和毒有害氣體就成為重要問題。在氣體傳感器中，金屬氧化物型半導體式氣體傳感器性能優(yōu)良、成本低廉。在本文中選擇氧化鎳半導體材料為基體材料。但是由于純半導體金屬氧化物材料的靈敏度不夠高，選擇性也較差。因此我們對氧化鎳半導體材料進行了改性。 在本文中，主要采取兩個方面對氧化鎳材料的氣敏性能進行改善：首先，利用半導體復合技術改善氧化鎳材料氣敏性能；其次，利用原位摻雜技術對氧化鎳材料進行改性。具體如下： 通過水熱法合成NiO空心材料。利用XRD、SEM、BET等表征手段對合成材料下進行了系統(tǒng)的表征。并將合成的NiO空心材料制備成氣體傳感器并進行了氣敏性能測試。結(jié)果表明，，空心結(jié)構(gòu)的NiO材料制備的氣體傳感器有良好的敏感性能。NiO空心結(jié)構(gòu)納米材料基氣體傳感器對甲苯、二甲苯有最高的響應度，說明NiO空心結(jié)構(gòu)納米材料有成為優(yōu)異甲苯、二甲苯氣體傳感器的潛力。 利用半導體復合技術對NiO材料進行改性。通過水熱法合成Fe3O4-NiO核殼結(jié)構(gòu)復合材料。Fe3O4的復合明顯提高了NiO傳感器對甲苯及二甲苯氣體的靈敏度和選擇性。在Fe3O4-NiO復合材料最佳工作溫度280oC下，復合后的傳感器對100ppm甲苯的靈敏度約為復合前的3倍。選擇性在復合后也有一定的提高。傳感器在復合后對甲苯氣體傳感性能提升主要原因可能是異質(zhì)結(jié)的勢壘高度在目標氣體和空氣中的變化。 針對NiO氣體傳感器選擇性較差的問題，利用原位摻雜的技術對NiO材料進行改性，可以很好地解決這一問題。首先利用水熱法合成Cr摻雜NiO材料并制作成氣體傳感器，研究了Cr摻入量對傳感器性能的影響。結(jié)果表明Cr摻雜使得器件的最佳工作溫度有明顯的升高，并且摻雜濃度為2at%的Cr-NiO納米材料對二甲苯有最高的響應度。除此之外，Cr摻雜后的NiO氣體傳感器的選擇性能有非常明顯的提高。Cr摻雜后的NiO氣體傳感器對二甲苯、甲苯的靈敏度提高的原因主要由兩個方面。首先是Cr的摻雜導致表面氧空位增加，提升了表面氧化能力。其次是Cr3+或Cr2O3在器件最佳工作溫度下對甲基有非常好的催化效應。器件選擇性的提高也主要歸因與Cr3+或Cr2O3的催化效應。
[Abstract]:Nowadays, with the rapid development of science and technology and the rapid improvement of people's living standard, people pay more and more attention to all kinds of problems. Among them, air pollution is becoming more and more serious, flammable and explosive gases and poisonous and harmful gases are harming people's health all the time. Therefore, how to effectively monitor and detect flammable, explosive and toxic gases in the environment has become an important issue. In gas sensor, metal oxide semiconductor gas sensor has good performance and low cost. In this paper, the nickel oxide semiconductor material is selected as the substrate material. However, the sensitivity and selectivity of pure semiconductor metal oxide materials are not high enough. Therefore, we modified the nickel oxide semiconductor material. In this paper, the gas sensing properties of nickel oxide materials were improved in two aspects: firstly, the semiconductor composite technology was used to improve the gas sensing properties of nickel oxide materials; secondly, in situ doping technology was used to modify nickel oxide materials. The details are as follows: NiO hollow materials were synthesized by hydrothermal method. The synthetic materials were systematically characterized by XRDX SEMX BET and so on. The NiO hollow material was prepared into a gas sensor and its gas sensing performance was tested. The results show that the gas sensor prepared by hollow structure NiO material has good sensitivity. Nio hollow structure nano-material gas sensor has the highest responsivity to toluene and xylene. The results show that NiO hollow nanostructure has the potential to be an excellent gas sensor for toluene and xylene. NiO materials were modified by semiconductor composite technology. The composite of Fe3O4-NiO core-shell structure composite 路Fe _ 3O _ 4 was synthesized by hydrothermal method. The sensitivity and selectivity of NiO sensor to toluene and xylene gas were improved obviously. The sensitivity of the composite sensor to 100ppm toluene is about three times as high as that of the former at the optimum working temperature of Fe3O4-NiO composite 280oC. The selectivity is also improved after recombination. The main reason for the improvement of the performance of the sensor is the variation of the barrier height of the heterojunction in the target gas and the air. In order to solve the problem of poor selectivity of NiO gas sensor, in situ doping technology can be used to modify NiO materials. Firstly, the Cr doped NiO material was synthesized by hydrothermal method and the gas sensor was fabricated. The effect of Cr content on the performance of the sensor was studied. The results show that Cr doping can obviously increase the optimal operating temperature of the device, and the Cr-NiO nanocrystalline with doping concentration of 2 at% has the highest responsivity to xylene. In addition, the selective performance of Cr doped NiO gas sensor is obviously improved. The main reasons for the increase of sensitivity of NiO gas sensor after Cr doping are two aspects. Firstly, the doping of Cr leads to the increase of oxygen vacancy on the surface, which improves the oxidation ability of the surface. Secondly, Cr3 or Cr2O3 have very good catalytic effect on methyl at the optimum operating temperature. The improvement of device selectivity is also attributed to the catalytic effect of Cr3 or Cr2O3.
【學位授予單位】：吉林大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN304.2;TB383.1

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本文編號：1867149