贵金属修饰的多孔ZNO复合材料对苯类气体敏感性能研究
发布时间：2018-12-25 10:17
【摘要】：近年来,随着科学技术的快速发展,环境污染问题越来越严重。周围环境中可能存在着各种有毒有害易燃易爆气体,其潜在的影响着人们的日常生活和生产活动,因此,如何及时监测这些危害性气体引起人们高度的重视。苯类化合物作为重要的有机溶剂广泛应用于多种家居用品和工业产品,所以苯类气体污染普遍存在于住宅区及工业环境中。由于苯类气体的剧毒性和致癌性,长时间处于低浓度的环境气氛也会对身体健康造成极大的伤害,所以检测低浓度的苯类气体是一项重要的任务。目前为止,多种半导体金属氧化物气体传感器已应用于苯类气体检测,然而苯类分子具有高的反应活化能和化学稳定性,使其检测难度大大增加,所以现有的苯类半导体气体传感器都存在着一些缺陷,例如灵敏度低,工作温度高,检测限高,响应-恢复时间长等。ZnO是一种典型的半导体金属氧化物敏感材料,已有很多关于其检测苯类气体的研究,但是这些研究方法同样存在着上述的问题,为了解决这些检测难点我们对ZnO材料进行了改性研究,通过修饰具有催化活性的贵金属提高ZnO半导体材料对苯类气体的传感性能。(1)选用贵金属Au作为修饰剂,通过温和的溶剂热和简单的热处理方法制备多孔Au/ZnO复合材料,该复合材料对苯类气体表现出优异的气敏性能。其中1 wt.%Au/ZnO复合材料对100 ppm苯的响应值最高且达到60,是纯ZnO响应值的5倍。另外,1wt.%Au/ZnO传感器具有低的检测限(0.5ppm),低的工作温度(260℃),快速的响应-恢复时间,长期的循环稳定性,并且苯浓度与响应值的对数呈现很好的线性关系。分析认为Au/ZnO复合材料苯敏性能的提高主要源于Au的催化作用和肖特基势垒。(2)通过上述的制备方法获得痕量Pt负载的ZnO复合材料,气敏测试发现Pt负载也可大幅度提高ZnO材料对苯、甲苯、二甲苯气体的气敏性能。系统研究得出基于0.1 wt%Pt-ZnO的气体传感器表现出最佳的气敏性能,在250℃的工作温度下对100 ppm苯的响应值能达到70。值得一提的是,其能快速的检测出100 ppb苯,达到室内苯类污染物的安全检测标准。Pt-ZnO复合材料对苯类气体杰出的响应特性归因于贵金属Pt的催化活性,肖特基势垒和p-n异质结的电子效应。
[Abstract]:In recent years, with the rapid development of science and technology, environmental pollution is becoming more and more serious. There may be a variety of toxic, harmful, flammable and explosive gases in the surrounding environment, which have a potential impact on people's daily life and production activities. Therefore, how to monitor these harmful gases in time has attracted great attention. Benzene compounds as important organic solvents are widely used in a variety of household products and industrial products, so benzene gas pollution generally exists in residential areas and industrial environment. Because of the high toxicity and carcinogenicity of benzene gas, it is an important task to detect benzene gas in low concentration environment for a long time. Up to now, many kinds of semiconductor metal oxide gas sensors have been applied to the detection of benzene gases. However, benzene molecules have high reaction activation energy and chemical stability, which greatly increase the difficulty of their detection. Therefore, the existing benzene semiconductor gas sensors have some defects, such as low sensitivity, high operating temperature, high detection limit, long response-recovery time, etc. ZnO is a typical semiconductor metal oxide sensitive material. There have been many studies on the detection of benzene gases, but these research methods also have the above problems. In order to solve these difficulties, we have studied the modification of ZnO materials. The sensing properties of ZnO semiconductor materials to benzene gases were improved by modifying the noble metals with catalytic activity. (1) the porous Au/ZnO composites were prepared by mild solvothermal and simple heat treatment with noble metal Au as modifier. The composite exhibits excellent gas sensitivity to benzene gases. The response value of 1 wt.%Au/ZnO composite to 100 ppm benzene was the highest and reached 60, which was 5 times of that of pure ZnO. In addition, 1wt.%Au/ZnO sensors have low detection limit (0.5ppm), low operating temperature (260 鈩，
本文编号：2391048
[Abstract]:In recent years, with the rapid development of science and technology, environmental pollution is becoming more and more serious. There may be a variety of toxic, harmful, flammable and explosive gases in the surrounding environment, which have a potential impact on people's daily life and production activities. Therefore, how to monitor these harmful gases in time has attracted great attention. Benzene compounds as important organic solvents are widely used in a variety of household products and industrial products, so benzene gas pollution generally exists in residential areas and industrial environment. Because of the high toxicity and carcinogenicity of benzene gas, it is an important task to detect benzene gas in low concentration environment for a long time. Up to now, many kinds of semiconductor metal oxide gas sensors have been applied to the detection of benzene gases. However, benzene molecules have high reaction activation energy and chemical stability, which greatly increase the difficulty of their detection. Therefore, the existing benzene semiconductor gas sensors have some defects, such as low sensitivity, high operating temperature, high detection limit, long response-recovery time, etc. ZnO is a typical semiconductor metal oxide sensitive material. There have been many studies on the detection of benzene gases, but these research methods also have the above problems. In order to solve these difficulties, we have studied the modification of ZnO materials. The sensing properties of ZnO semiconductor materials to benzene gases were improved by modifying the noble metals with catalytic activity. (1) the porous Au/ZnO composites were prepared by mild solvothermal and simple heat treatment with noble metal Au as modifier. The composite exhibits excellent gas sensitivity to benzene gases. The response value of 1 wt.%Au/ZnO composite to 100 ppm benzene was the highest and reached 60, which was 5 times of that of pure ZnO. In addition, 1wt.%Au/ZnO sensors have low detection limit (0.5ppm), low operating temperature (260 鈩，
本文编号：2391048
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