为了改善传统的气体传感器性能,将Ag-ZSM-5沸石与SnO2材料以直接混合法制成复合气敏元件。用XRD、SEM、TEM分别对ZSM-5和Ag-ZSM-5两种沸石进行了表征测试与分析。制备了SnO2、SnO2/ZSM-5和/Ag-ZSM-5三种气体传感器进行了VOC气体的气敏对比测试。实验结果表明,与纯SnO2传感器相比,SnO2与Ag-ZSM-5混合的复合材料大幅改善了对甲醛气体的响应值。在检测50 ppm浓度的甲醛气体时,与SnO2传感器相比,加入ZSM-5沸石材料后,响应值提高了36%;而加入Ag-ZSM-5沸石材料后,响应值提高了121%。为了验证实验结果的准确性以及探索Ag-ZSM-5沸石在微观方面对吸附气体的影响,结合基于DFT的第一性原理分析了Ag-ZSM-5沸石对甲醛气体分子气敏特性改善的机理。
Abstract
To enhance the performance of the conventional SnO2 gas sensor, a composite gas sensor was fabricated by directly mixing Ag-ZSM-5 zeolite and SnO2 material. The ZSM-5 and Ag-ZSM-5 zeolites were characterized using XRD, SEM and TEM. Three types of gas sensors, including SnO2, SnO2/ZSM-5 and SnO2/Ag-ZSM-5, were prepared to evaluate their sensitivity towards VOC gas. Experimental results demonstrated that the incorporation of Ag-ZSM-5 zeolite into SnO2 composite considerably enhanced the response value to formaldehyde gas, compared to the pure SnO2 sensor. Specifically, the response value increased by 36% after introducing ZSM-5 zeolite when the formaldehyde gas concentration was 50 ppm; whereas the response value increased by 121% after adding Ag-ZSM-5 zeolite. To verify the reliability of the experimental results and investigate the microscopic impact of Ag-ZSM-5 zeolite on gas adsorption, the mechanism behind the improvement in gas sensitivity of Ag-ZSM-5 zeolite towards formaldehyde gas molecules was analyzed based on the first principle of DFT.
关键词
气体传感器 /
DFT /
沸石 /
SnO2
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Key words
gas sensor /
DFT /
zeolite /
SnO2
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参考文献
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脚注
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基金
辽宁省自然科学基金项目(2022-BS-102)。
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