摘要
采用以离子交换法制备的Fe-ZSM-5、Fe-MCM-22和Fe-Beta分子筛催化剂,系统地考察了分子筛构型、酸性和酸中心分布对N_2O直接催化分解的影响。采用N_2吸附、红外光谱仪(FT-IR)、NH_3程序升温脱附实验(NH_3-TPD)、H_2程序升温还原实验(H_2-TPR)和原位漫反射红外光谱(in situ DRIFTS)等方法考察了铁离子负载量、Si与Al摩尔比和分子筛构型对N_2O催化分解的影响。结果表明,价键补偿Fe^(3+)离子是N_2O分解的主要活性组分;分子筛活性随Si和A1摩尔比的减少和铁离子负载量的增加而增加;Fe-Beta分子筛的催化活性明显高于Fe-ZSM-5和FeMCM-22分子筛;分子筛酸性和酸中心分布影响铁离子的分布,从而导致不同构型分子筛催化分解N_2O的活性具有明显差异。
The effects of zeolite type, acidity and acid center distribution on N2O catalytic decomposition over Fe-modified zeolites prepared by ion-exchange were investigated and the effects of iron-ions loading, the molar ratio of Si to Al and zeolite type on N2O catalytic decomposition were studied by means of N2-adsorption, FT-IR, H2-temperature programmed reduction （H2-TPR）, NH3-temperature programmed desorption （NH3-TPD） and in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS）. The results showed that the Fe-ZSM-5 zeolite activity increased with the decrease of the molar ratio of Si to Al and the increase of Fe-ions loading. The catalytic activity of Fe-Beta zeolite was higher than that of the Fe-ZSM-5 and Fe-MCM-22 zeolite. Fe^3＋ as change-balancing cations was the main active component in N2O catalytic decomposition reaction. The acidity and acid center distribution of zeolite had important influence on the distribution of iron-ions loading over zeolite channel and the distribution of iron-ions loading resulted in the obviously difference of activity of different zeolite in the catalytic decomposition of N2O reaction.
出处
《化学反应工程与工艺》
EI
CAS
CSCD
北大核心
2007年第4期337-342,共6页
Chemical Reaction Engineering and Technology
基金
国家杰出青年科学基金(20625621)
关键词
分子筛
一氧化二氮
催化分解
酸性
酸中心分布
zeolite
nitrous oxide
catalytic decomposition
acidity
acid center distribution
