氧化物掺杂二氧化锡基气体传感器的气体检测特性研究

发布时间：2018-04-03 18:04

本文选题：H2和CO　切入点：氧化铜掺杂　出处：《重庆大学》2014年硕士论文

【摘要】：油中溶解特征气体分析是对电力变压器进行状态检修的有效方法之一，氢气(H2)和一氧化碳(CO)属于变压器油中溶解的主要故障特征气体，能有效反应电力变压器的电性、热性故障或油纸绝缘问题。气体传感技术是实现油中溶解气体在线分析的关键。半导体二氧化锡气体传感器因具有成本低、灵敏度高且易于维修等优势而受到了广泛的关注。为了解决目前半导体传感器存在的稳定性、选择性差和使用寿命短等诸多问题，开始采用一些新型的气体传感技术对油中溶解气体进行在线监测，以达到实际工程应用的要求。深入研究气体传感器及其检测特性对提升传感器的气体检测技术具有重要意义。论文针对氧化铜和氧化锌掺杂的二氧化锡基纳米气体传感器对气体H2和CO的气体检测特性，介绍其制备方法和实验步骤，并利用X射线衍射(XRD)、场发射扫描电镜(FESEM)、透射电子显微镜(TEM)以及高分辨率的透射电镜(HRTEM)对制备的CuO-SnO2、ZnO-SnO2及SnO2纳米粉末进行形貌表征分析，分析其气敏机理。结果表明： ①通过形貌表征分析得出：CuO-SnO2纳米材料的气敏性能提高是由于p-n结与肖特基势垒之间的变换以及吸附氧和异质结的影响。ZnO-SnO2材料性能的改变主要是由于ZnO的掺杂形成了异质结并改变了晶粒大小；异质结的产生促进了电子的迁移，加强了气敏特性；晶粒直径的减小，导致比表面积增大，从而使传感器的气敏响应特性提高。 ②通过气敏实验发现，相比SnO2纳米传感器，本文研究的CuO-SnO2和ZnO-SnO2新型纳米气体传感器对油中溶解气体H2和CO具更高的灵敏度和分辨力，线性度、稳定性及响应-恢复特性好，最佳工作温度也有所降低。传感器的灵敏度随着工作温度的提高而增大，，当温度过高时，即工作温度大于其最佳工作温度，高温使材料表面的化学吸附氧的解吸速率大于其吸附速率，导致灵敏度降低。同时，CuO-SnO2和ZnO-SnO2纳米气体传感器对H2和CO具有较好的选择性，能有效地将这两种气体与CH4、C2H6、C2H4和C2H2气体进行区分。 ③本文研究的CuO-SnO2和ZnO-SnO2纳米气体传感器有效提升了对变压器油中溶解H2和CO气体的气敏特性，为复合二氧化锡基气体传感器的研究提供了一种新的思路。
[Abstract]:Analysis of dissolved gas in oil is one of the effective methods for condition maintenance of power transformer, hydrogen (H2) and carbon monoxide (CO) belongs to the main fault gases dissolved in transformer oil, electric power transformer can effectively response, thermal insulation fault or oil. The gas sensing technology is a key analysis solution the oil gas line. Two semiconductor oxide gas sensor with low cost, high sensitivity and easy maintenance and other advantages have attracted much attention. In order to solve the stability of semiconductor sensors exist, such as short service life and poor selectivity to many problems, the on-line monitoring of dissolved gas in oil by using some new gas sensing technology, to meet the requirements of practical engineering application.
Further study of gas sensor and its detection performance has important significance to improve the sensor gas detection technique. The characteristics of gas detection sensor two tin oxide based nano gas in copper oxide and doped H2 gas on Zinc Oxide and CO, introduced the preparation methods and experimental steps, and using X ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) on the preparation of CuO-SnO2, ZnO-SnO2 and SnO2 nano powder morphology characterization analysis, analysis results show that the gas sensing mechanism:
The morphology characterization analysis: to improve gas sensing properties of CuO-SnO2 nano material is due to p-n between the junction and the Schottky barrier transform and change affect the adsorption of oxygen and the heterojunction properties of.ZnO-SnO2 materials is mainly due to the formation of ZnO doped heterojunction and change the grain size; electron migration promoted heterostructure. Strengthen the gas sensitivity; decrease of grain diameter, resulting in increased surface area, so that the gas sensor response characteristic is improved.
The gas sensing experiments show that compared with SnO2 nano sensor, sensitivity of CuO-SnO2 and ZnO-SnO2 nano gas sensor research on higher dissolved gas in oil H2 and CO with the resolution and linearity, stability and response recovery characteristics, the optimum temperature is reduced. The sensitivity of the sensor increases with the work the increase of temperature, when the temperature is too high, the working temperature is greater than that of its best working temperature, high temperature and the chemical adsorption oxygen desorption rate of material surface is greater than the adsorption rate, lower sensitivity. At the same time, CuO-SnO2 and ZnO-SnO2 nano gas sensor has good selectivity to H2 and CO, can effectively separate the two gases and CH4, C2H6, C2H4 and C2H2 to distinguish gas.
(3) the CuO-SnO2 and ZnO-SnO2 nano gas sensors studied in this paper effectively enhance the gas sensing characteristics of dissolved H2 and CO gas in transformer oil, and provide a new way for the study of composite two tin oxide based gas sensors.

【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM41;TP212

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