沸石基氨气传感器的性能研究

发布时间：2018-09-12 06:02

【摘要】：近年来,沸石在气体传感器领域得到了越来越多的关注。由于沸石的多孔性和离子交换性能,使其在提高气体传感器的灵敏度和选择性方面具有独特的优势。本文尝试将沸石材料作为阻抗型氨气传感器的功能材料,探索其气敏性能。首先,采用水热法合成方法A型和Y型沸石粉末,并对Y型沸石粉末进行不同温度的烧结处理,通过对烧结后Y型沸石粉末的XRD测试结果进行分析,判定Y型沸石粉末作为功能材料的最佳烧结温度为600℃。其次,采用Y型沸石粉末为功能材料,用银浆作电极以丝网印刷工艺制备出电容式结构的沸石基阻抗型氨气传感器。为使得传感器获得最大的响应值,本文以Na-Y型沸石基传感器为例,给传感器加上六种不同的激励频率,测试其分别对100 ppm NH3的响应,并测试其在不同浓度氨气下响应的阻抗谱。测试结果表明:传感器的激励频率为3 k Hz时,传感器对氨气有良好的响应,因此后续实验均采取3 k Hz作为传感器的最佳激励频率。此外,在150~250℃的工作温度,一定气氛条件下,测试该传感器对NH3气体的响应特性,测试结果显示:Na-Y型沸石基传感器对100 ppm NH3的响应值达36.2%,且传感器最佳工作温度为200℃。第三,本文采用液相离子交换法对Na-Y型沸石中Na+进行离子交换,交换的元素分别为质子H+,碱金属元素Li+,稀土元素La3+,贵金属元素Pd2+和Ag+,采用每一种元素可溶性的盐溶液。将不同离子交换制备成传感器,在相同的测试条件下,对其进行上述各项测试,并与Na-Y型沸石基传感器的性能作对比。结果显示:使用Ni+、La3+以及Ag+交换制备的传感器的响应性能均有所提高,但对于H+和Pd2+交换制备的传感器的响应值却不及Na-Y型沸石基传感器。同时,对Ag-Y型沸石基传感器进行选择性测试以及对O2的抗干扰能力测试,实验结果表明:传感器对CO2与CO存在良好的选择性,对不同体积分数的O2对传感器无影响,但C3H6与NO对传感器存在微弱影响。第四,改变传感器的厚度探究改进后的传感器对氨气的响应,并设计出不同厚度的传感器厚度。将不同厚度的Ag-Y型沸石基传感器,在相同的测试条件下,对其进行上述各项性能测试。研究结果表明:随着沸石基传感器的厚度增加,传感器对氨气响应程度也随之增加。最后,本文尝试使用A型沸石与ZSM-5型沸石代替Y型沸石,制备了相同结构的电容式沸石基传感器,同时用相同浓度的Ag NO3溶液使用离子交换法对A型沸石与ZSM-5型沸石中的阳离子进行置换,制备出Ag-A型沸石基传感器与Ag-ZSM-5型沸石基传感器,探索研究改进后传感器对NH3气体的响应特性。结果显示:Na-A型与Ag-A型沸石基传感器对氨气不响应,H-ZSM-5型与Ag-ZSM-5型沸石基传感器对氨气均有一定响应,且前者响应大于后者。总之,本文系统研究了用于检测氨气的沸石基传感器的一些性能,重点探究了Y型沸石基氨气传感器的性能。实验结果表明:可以使用Ag-Y型沸石基传感器对检测氨气具有良好效果。
[Abstract]:In recent years, zeolite has attracted more and more attention in the field of gas sensors. Because of its porous and ion exchange properties, zeolite has unique advantages in improving the sensitivity and selectivity of gas sensors. Firstly, zeolite A and zeolite Y powders were synthesized by hydrothermal method, and the zeolite Y powders were sintered at different temperatures. By analyzing the XRD results of the sintered zeolite Y powders, the optimum sintering temperature of zeolite Y powders as functional materials was determined to be 600 C. Secondly, zeolite Y powders were used as functional materials and silver was used as functional materials. Zeolite-based impedance ammonia sensor with capacitive structure was fabricated by screen printing with slurry as electrode. In order to maximize the response of the sensor, the Na-Y zeolite-based sensor was used as an example. Six different excitation frequencies were added to the sensor to test its response to 100 ppm NH3, and its response to different concentrations of ammonia was tested. The results show that the sensor has a good response to ammonia when the excitation frequency of the sensor is 3 K Hz. Therefore, the optimal excitation frequency of the sensor is 3 K Hz in the following experiments. In addition, the response characteristics of the sensor to NH3 gas are tested at the operating temperature of 150-250 C and under certain ambient conditions. The results show that the response value of the Na-Y zeolite-based sensor to 100 ppm NH3 is 36.2%, and the optimum working temperature of the sensor is 200 C. Thirdly, the ion exchange of Na + in Na-Y zeolite is carried out by liquid-phase ion exchange method. The exchanged elements are proton H +, alkali metal element Li +, rare earth element La3 +, precious metal element Pd2 + and Ag +, and each of them is used. Soluble salt solution of elements. Sensors prepared by different ion exchanges were tested under the same test conditions and compared with Na-Y zeolite-based sensors. The results showed that the response of sensors prepared by Ni+, La3+ and Ag+ exchanges was improved, but for H + and Pd2+ exchanges, the performance of sensors was improved. At the same time, the selectivity of Ag-Y zeolite-based sensor and the anti-interference ability of O2 were tested. The results showed that the sensor had good selectivity to CO2 and CO, and had no effect on the sensor with different volume fraction of O2, but C3H6 and NO had weak effect on the sensor. Fourth, change the thickness of the sensor to explore the response of the improved sensor to ammonia, and design different thickness of the sensor. Different thickness of Ag-Y zeolite-based sensors, under the same test conditions, to carry out the above performance tests. The results show that: with the increase of the thickness of the zeolite-based sensor, transmission. Finally, the capacitive zeolite-based sensor with the same structure was prepared by using zeolite A and zeolite ZSM-5 instead of zeolite Y. At the same time, the cations in zeolite A and zeolite ZSM-5 were replaced by ion exchange method in the same concentration of Ag-NO3 solution. The results show that the Na-A and Ag-A zeolite-based sensors are not responsive to ammonia, and the H-ZSM-5 and Ag-ZSM-5 zeolite-based sensors have certain responses to ammonia, and the former is more responsive than the latter. Some properties of zeolite-based ammonia sensor used for detecting ammonia are studied, especially the performance of Y-type zeolite-based ammonia sensor. The experimental results show that the Ag-Y type zeolite-based ammonia sensor can be used to detect ammonia with good results.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP212

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