HZSM5分子筛膜复合二氧化锡对甲烷的气敏性能研究

采用液相氧化法制备二氧化锡纳米颗粒,并利用浸渍法制备Pd负载二氧化锡纳米材料,通过丝网印刷得到气敏传感膜并在其表面印刷分子筛层。基于动态气敏测试系统探究传感器对甲烷气体的灵敏度及其在CO和乙醇干扰气体下的选择性。研究结果表明,在Pd-SnO₂敏感层表面印刷Pd-HZSM5层后,传感器对甲烷的响应能力显著提高,并且在体积分数为5×10^-4的CO存在时,对甲烷的选择性也得到明显的提升。同样,在质量分数为2×10^-5乙醇的存在下,传感器对甲烷的响应也没有受到干扰。通过对分子筛进行表征和催化分析,发现Pd-HZSM5对CO的催化效率可达100%,使得CO在扩散过程中被催化氧化,这可能是印刷Pd-HZSM5分子筛膜从而提高传感器选择性的主要原因。同时研究还表明,在敏感层表面印刷分子筛层并不会影响传感器的响应和恢复速率。

Study on gas sensitivity of HZSM5 zeolite film combined with SnO2 for methane

SnO2 nanoparticles were prepared by oxidation process in liquid and Pd-loaded SnO2 nano-sized material by impregnation method was synthesized.Gas sensors based on Pd-loaded SnO2 nanoparticles were prepared by screen-printing and coated with an overlayer of zeolite layer.Based on the dynamic gas sensing test system,the sensitivity of the gas sensor for methane and its selectivity under the interference of CO and ethanol gas were investigated.The results showed that after printing Pd-HZSM5 layer on the surface of Pd-SnO2 sensitive layer,the response ability of the sensor for methane was significantly improved,and the selectivity to methane was also significantly improved in the presence of 5×10^-4(volume fraction)CO.Similarly,in the presence of 2×10^-5(mass fraction)ethanol,the sensor response to methane was not disturbed.Through the characterization and catalytic analysis of the molecular sieve,it was found that the catalytic efficiency of Pd-HZSM5 for CO reached100%,which led CO be catalytically oxidized in the diffusion process.This may be the main reason for printing the Pd-HZSM5 molecular sieve membrane to improve the selectivity of the sensor.Meanwhile,the research also showed that printing molecular sieve layer on the surface of the sensitive layer will not affect the response and recovery rate of the sensor.