ZnO复合纳米材料的合成及其气敏特性的研究

发布时间：2018-06-22 00:35

本文选题：ZnO + 复合材料　；参考：《吉林大学》2017年硕士论文

【摘要】：人类的生活环境与周围的环境气体是密不可分的。环境中大气污染气体主要包括含硫、碳、氮化合物,碳氢化合物和卤素化合物。伴随着科学技术的发展和生活方式的现代化,一个人平均每天约超过80%的时间是在室内度过的。因此,室内空气质量同样直接影响着人类身体健康。TVOC(总挥发有机物)是影响室内空气质量最为严重的一类气体,它具有致癌性、对人的皮肤和粘膜产生刺激性,并且在常温条件下就可以气态存在与空气当中,成为人类健康的潜在“杀手”。然而,对于目前应用最广泛的气体传感器-金属氧化物半导体气体传感器来说,普遍存在选择性和灵敏度上的不足。对于ZnO气敏传感器来说,存在着灵敏度较低、选择性和稳定性较差的缺点。对于金属氧化物半导体型气体传感器来说,气敏材料的微观尺寸、组成和结构对气敏性能(灵敏度、响应恢复时间、稳定性等)有着决定性的作用。一方面,对于金属氧化物半导体纳米材料来说,中空/核壳结构减小了粒子的团聚,其表面疏松多孔,利于待测气体的渗透,进而明显提高反应速率和灵敏度。另一方面,纳米复合材料(具有强的界面相互作用和大的比表面积)在检测气体时具有协同作用,有利于灵敏度的提高。因此,本论文将两种优势结合制备两种基于ZnO的中空/核壳结构的复合材料,并用于气敏性能的测试。具体工作主要如下:(1)首先利用葡萄糖作为前驱物通过水热法合成出碳球,然后利用碳球作为模板,制备了中空Zn Fe_2O_4-ZnO复合球,并将材料涂覆成器件用于丙酮气体的气敏性能测试。XRD、EDS-mapping测试结果显示,Zn Fe_2O_4纳米粒子和ZnO纳米粒子相互复合在一起形成中空Zn Fe_2O_4-ZnO复合球,而不是形成固溶体或者孤立的中空球。测试结果表明,相比于Zn Fe_2O_4-ZnO复合粒子,中空Zn Fe_2O_4-ZnO复合球对于丙酮气体在相同工作温度下具有更高的灵敏度。且中空Zn Fe_2O_4-ZnO复合球不仅对丙酮气体,也对甲苯、三甲胺、氨气具有较快的响应恢复速率。(2)首先利用葡萄糖作为前驱物通过水热法合成出碳球,以其为模板,合成出中空SnO_2球,然后利用表面活性剂在SnO_2核外面包裹一层ZnO壳,形成独特的核-中空-壳的结构,并将核壳SnO_2@ZnO球用于乙醇气体的气敏性能测试。气敏测试结果表明,相比于中空SnO_2球和ZnO纳米粒子,核壳SnO_2@ZnO球对乙醇气体具有更高的灵敏度,并且对于50 ppm乙醇气体响应时间短至0.4s。本论文研究的两种材料均为中空、表面多孔结构的复合材料。气敏性能测试结果证明了将材料进行微观形貌和组成成分的改变是提升其敏感性能的一个有效途径。论文丰富了微观尺度下材料的形貌、成分与宏观敏感功能之间的关系,为发展具有中空/核壳结构的新型复合材料应用于气体传感器领域上提供了更多的可能。
[Abstract]:The living environment of human beings is inseparable from the ambient gas. The atmosphere pollution gases in the environment include sulfur, carbon, nitrogen compounds, hydrocarbons and halogen compounds. With the development of science and technology and the modernization of life style, an average of about 80% of the time per day is spent in the room. Therefore, indoor air is empty. Gas quality also directly affects human health.TVOC (total volatile organic matter) is the most serious kind of gas which affects the quality of indoor air. It is carcinogenic, irritating to human skin and mucous membrane, and can be the potential "killer" of human health under the condition of normal temperature. For the most widely used gas sensors - metal oxide semiconductor gas sensors, there is a general shortage of selectivity and sensitivity. For ZnO gas sensors, there are shortcomings of low sensitivity, selectivity and poor stability. For metal oxide semiconductor gas sensors, gas sensitive materials Micro size, composition and structure have a decisive effect on the gas sensitivity (sensitivity, response time, stability, etc.). On the one hand, for the metal oxide semiconductor nanomaterials, the hollow / shell structure reduces the agglomeration of particles, and the surface is porous and porous, which is beneficial to the permeation of the gases to be measured, and then the reaction rate is obviously improved. Sensitivity. On the other hand, nanocomposites (with strong interface interaction and large specific surface area) have synergistic effects in detecting gas, which is beneficial to the enhancement of sensitivity. Therefore, this paper combines two kinds of advantages to prepare two ZnO based composite materials of hollow / shell structure, and use it to test the gas sensitivity. The main results are as follows: (1) first, the carbon spheres are synthesized by the hydrothermal method using glucose as a precursor. Then the hollow Zn Fe_2O_4-ZnO composite ball is prepared by using the carbon sphere as a template. The material is coated into a device to test the gas sensitivity performance of acetone gas.XRD. The results of EDS-mapping test show that Zn Fe_2O_4 nanoparticles and ZnO nanoparticles are in phase. The hollow Zn Fe_2O_4-ZnO composite ball is formed together, not the solid solution or the isolated hollow sphere. The test results show that the hollow Zn Fe_2O_4-ZnO composite ball has a higher sensitivity to the acetone gas at the same working temperature compared to the Zn Fe_2O_4-ZnO composite particles. And the hollow Zn Fe_2O_4-ZnO composite ball is not only to C. The ketone gas also has a fast response recovery rate for toluene, trimethylamine and ammonia. (2) first, the carbon spheres were synthesized by the hydrothermal method using glucose as a precursor, and the hollow SnO_2 ball was synthesized as a template. Then a layer of ZnO shell was wrapped outside the nucleus of SnO_2 by surfactants to form a unique core hollow shell structure, and the core shell Sn was formed. The O_2@ZnO ball is used to test the gas sensitivity of the ethanol gas. The gas sensitivity test results show that compared to the hollow SnO_2 ball and the ZnO nanoparticles, the nuclear shell SnO_2@ZnO ball has higher sensitivity to the ethanol gas, and the two materials of the 50 ppm ethanol gas response time short to 0.4s. are all hollow and the surface porous structure is complex. The test results of gas sensitivity show that the change of the microstructure and composition of the material is an effective way to improve the sensitivity of the material. The paper enriches the relationship between the morphology, the composition and the macro sensitive function of the material at the micro scale, and is applied to the development of a new type of composite material with hollow / shell structure for the development of gas transmission. More possibilities are provided in the sense organ.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212;TB383.1

【参考文献】