ZnO一维纳米材料制备、修饰、介电泳操控及气敏传感器构建研究
发布时间：2018-09-17 17:14
【摘要】：随着生态环境的恶化,对环境进行高效、实时监控的迫切需要对气体传感器的性能提出了更高的要求。如何提高选择性、长期工作稳定性以及响应-恢复速度、降低功耗和成本是新型气体传感器面临的主要挑战。因此,开发新型气敏材料、探索新的气敏机制和设计新的器件结构成为该领域的重要研究方向。首先就气敏材料而言,目前广泛应用的是金属氧化物半导体材料。但是基于金属氧化物半导体材料的气体传感器多存在工作温度高、选择性差等问题,因此实用性强、高性能、低成本气体传感器的开发还有许多困难需要克服。材料科学的新技术为我们解决上述问题提供了有效途径。例如,针对气体传感器工作温度高、选择性差等缺点,可以通过对敏感材料进行贵金属表面修饰的方法加以改善。其次,就气敏元件的构建而言,新涌现的微纳米操控技术也可以大大降低微纳米结构器件构建对设备的要求和工艺难度,本课题采用介电泳技术操控一维纳米材料,将纳米材料跨界在电极两侧,构建成气体传感器。本课题采用化学水浴法制备氧化锌纳米棒,并对其气敏特性进行了研究。然而,由于单纯的氧化锌纳米棒在气体选择性、响应-恢复速度、灵敏度等方面,还难以满足实际应用的需要,因此对氧化锌纳米棒做进一步的修饰或复合处理具有极其重要的意义。另外,为了有效利用一维纳米材料在结构上的特殊优势,构建基于一维纳米材料有序定向排列的器件是必然方向。考虑降低设备要求和工艺难度,本课题采用了相对简单的介电泳操控技术构建了一维氧化锌有序排列的气体传感器用于材料气敏特性研究。本课题研究分为三个部分:第一部分:利用光化学沉积法,在氧化锌纳米棒表面进行银纳米颗粒修饰。实验中用聚乙烯吡咯烷酮作为稳定剂,使贵金属Ag纳米颗粒分散地附着在氧化锌纳米棒表面,形成Ag/ZnO异质结。除此之外,本实验还对比了两种不同的电极材料,即镍酸镧氧化物导体电极和Ag-Pd贵金属电极。实验发现分别采用两种电极材料的气敏元件在气敏特性方面没有明显差异,表明廉价的镍酸镧氧化物导体电极可以替代贵金属电极。第二部分:用光化学沉积法在氧化锌纳米棒表面制备Cu O/ZnO异质结,并测试其气敏特性。本实验采用不同浓度(25μM、50μM和200μM)的硝酸铜的水溶液作为前驱液,紫外灯下照射一段时间后得到CuO/ZnO异质结复合材料。并对样品进行气敏特性测试,结果发现样品对硫化氢最敏感,最佳工作温度为250℃。第三部分:制备MWCNT/Zn O异质结复合材料,并在室温下测试其气敏特性,测试结果表明该结构在室温下对二氧化氮气体比较敏感。并探讨MWCNT/ZnO异质结复合材料获得最佳气敏特性时,多壁碳纳米管(MWCNT)和氧化锌纳米棒的比例。
[Abstract]:With the deterioration of the ecological environment, the high efficiency of the environment and the urgent need of real-time monitoring put forward higher requirements for the performance of gas sensors. How to improve selectivity, long-term stability, response-recovery speed, and reduce power consumption and cost are the main challenges facing the new gas sensor. Therefore, developing new gas sensing materials, exploring new gas sensing mechanisms and designing new device structures are important research directions in this field. Firstly, as far as gas sensing materials are concerned, metal oxide semiconductors are widely used at present. However, many gas sensors based on metal oxide semiconductor materials have many problems such as high working temperature and poor selectivity, so there are still many difficulties to overcome in the development of gas sensors with high practicability, high performance and low cost. The new technology of material science provides an effective way for us to solve the above problems. For example, in view of the shortcomings of high temperature and poor selectivity of gas sensors, the surface modification of sensitive materials can be improved by the method of precious metal surface modification. Secondly, as far as the construction of gas sensors is concerned, the newly emerged micro / nano manipulation technology can greatly reduce the equipment requirements and process difficulties in the fabrication of micro / nano structure devices. In this paper, one dimensional nanomaterials are manipulated by using dielectric electrophoresis technology. A gas sensor was constructed by crossing the nanomaterials on both sides of the electrode. In this paper, zinc oxide nanorods were prepared by chemical water bath method and their gas sensing characteristics were studied. However, the pure ZnO nanorods are difficult to meet the needs of practical application in gas selectivity, response-recovery speed, sensitivity and so on. Therefore, further modification or composite treatment of ZnO nanorods is of great significance. In addition, in order to effectively utilize the special advantages of one-dimensional nanomaterials in structure, it is necessary to construct the devices based on ordered orientation of one-dimensional nanomaterials. In order to reduce the equipment requirement and process difficulty, a one-dimensional gas sensor with ordered arrangement of zinc oxide was constructed by using a relatively simple meso-electrophoretic manipulation technique to study the gas sensing characteristics of materials. The research is divided into three parts: the first part: the surface of zinc oxide nanorods was modified with silver nanoparticles by photochemical deposition. Using polyvinylpyrrolidone as stabilizer, noble metal Ag nanoparticles were dispersed on the surface of zinc oxide nanorods to form Ag/ZnO heterostructures. In addition, two different electrode materials, lanthanum nickel oxide conductor electrode and Ag-Pd noble metal electrode, were compared. It is found that there is no obvious difference in gas sensitivity between the two kinds of electrode materials, which indicates that the cheap lanthanum nickel oxide conductor electrode can replace the noble metal electrode. Part two: the Cu O/ZnO heterojunction was prepared on the surface of ZnO nanorods by photochemical deposition, and its gas sensing properties were tested. In this experiment, the aqueous solution of copper nitrate with different concentrations (25 渭 m ~ (50 渭 M) and 200 渭 M) was used as the precursor, and the CuO/ZnO heterojunction composite was obtained after irradiation by ultraviolet lamp for a period of time. The results show that the sample is most sensitive to hydrogen sulfide and the optimum working temperature is 250 鈩，
本文编号：2246580
[Abstract]:With the deterioration of the ecological environment, the high efficiency of the environment and the urgent need of real-time monitoring put forward higher requirements for the performance of gas sensors. How to improve selectivity, long-term stability, response-recovery speed, and reduce power consumption and cost are the main challenges facing the new gas sensor. Therefore, developing new gas sensing materials, exploring new gas sensing mechanisms and designing new device structures are important research directions in this field. Firstly, as far as gas sensing materials are concerned, metal oxide semiconductors are widely used at present. However, many gas sensors based on metal oxide semiconductor materials have many problems such as high working temperature and poor selectivity, so there are still many difficulties to overcome in the development of gas sensors with high practicability, high performance and low cost. The new technology of material science provides an effective way for us to solve the above problems. For example, in view of the shortcomings of high temperature and poor selectivity of gas sensors, the surface modification of sensitive materials can be improved by the method of precious metal surface modification. Secondly, as far as the construction of gas sensors is concerned, the newly emerged micro / nano manipulation technology can greatly reduce the equipment requirements and process difficulties in the fabrication of micro / nano structure devices. In this paper, one dimensional nanomaterials are manipulated by using dielectric electrophoresis technology. A gas sensor was constructed by crossing the nanomaterials on both sides of the electrode. In this paper, zinc oxide nanorods were prepared by chemical water bath method and their gas sensing characteristics were studied. However, the pure ZnO nanorods are difficult to meet the needs of practical application in gas selectivity, response-recovery speed, sensitivity and so on. Therefore, further modification or composite treatment of ZnO nanorods is of great significance. In addition, in order to effectively utilize the special advantages of one-dimensional nanomaterials in structure, it is necessary to construct the devices based on ordered orientation of one-dimensional nanomaterials. In order to reduce the equipment requirement and process difficulty, a one-dimensional gas sensor with ordered arrangement of zinc oxide was constructed by using a relatively simple meso-electrophoretic manipulation technique to study the gas sensing characteristics of materials. The research is divided into three parts: the first part: the surface of zinc oxide nanorods was modified with silver nanoparticles by photochemical deposition. Using polyvinylpyrrolidone as stabilizer, noble metal Ag nanoparticles were dispersed on the surface of zinc oxide nanorods to form Ag/ZnO heterostructures. In addition, two different electrode materials, lanthanum nickel oxide conductor electrode and Ag-Pd noble metal electrode, were compared. It is found that there is no obvious difference in gas sensitivity between the two kinds of electrode materials, which indicates that the cheap lanthanum nickel oxide conductor electrode can replace the noble metal electrode. Part two: the Cu O/ZnO heterojunction was prepared on the surface of ZnO nanorods by photochemical deposition, and its gas sensing properties were tested. In this experiment, the aqueous solution of copper nitrate with different concentrations (25 渭 m ~ (50 渭 M) and 200 渭 M) was used as the precursor, and the CuO/ZnO heterojunction composite was obtained after irradiation by ultraviolet lamp for a period of time. The results show that the sample is most sensitive to hydrogen sulfide and the optimum working temperature is 250 鈩，
本文编号：2246580
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