摘要
分别采用共沉淀法和浸渍法、不同铁前驱物以及不同焙烧温度等研究了制备工艺对Mn-Fe/ZSM-5催化剂的结构、化学组分及NH3-SCR活性的影响.结果显示,当采用Fe（NO3）3作为Fe前驱物,并用共沉淀法制备、300℃焙烧条件下得到的MFZ-CP-N-300样品低温活性最优,在120℃时,其NO的转化率达到96.7%,120~300℃范围内NO转化率始终保持在95%以上.同时利用XRD、NH3-TPD、XPS、SEM、TEM、氮吸附等手段对催化剂结构、晶相、酸位、锰铁氧化物的化学形态及表面的形貌特征进行表征分析.结果表明锰铁氧化物分别以Mn O2-Mn2O3和Fe2O3的形式高度分散于催化剂表面,特别是当Mn4＋/Mn3＋比例为1.254时,有较强的表面中强酸和较多的酸位数,从而增加了NH3的吸附能力,提高NO的转化率.
A series of Mn-Fe / ZSM-5 catalysts were prepared for the selective catalytic reduction（ SCR） of NO. Additionally,the effects of co-precipitation and impregnation methods,Fe precursors,and calcination temperatures on morphology,chemical composition,and the catalytic activity were investigated. The results indicated that Mn-Fe / ZSM-5 catalyst exhibited superior SCR activity and a broad active temperature range（ 120 ~ 300 ℃） when prepared by the co-precipitation method u sing Fe（ NO3）3as precursor and calcining it at 300 ℃. At 120 ℃,the conversion of NO achieved 96. 7%,and the NO conversion was always more than 95% in the temperature range 120 ~ 300 ℃. X-ray diffraction,ammonia-temperature programmed desorption,X-ray photoelectron spectroscopy,scanning electron microscopy,transmission electron microscope,N2-physisorption were used to characterized. Manganese and iron were mainly dispersed on the catalyst surface in the state of Mn O2-Mn2O3 and Fe2O3respectively,as evidenced by the combined result of XRD and XPS. Specifically,when the superior Mn4 ＋/ Mn3 ＋ratio is 1. 254 and the larger number and stronger intensity of acid sites,NH3 adsorption and NO reduction activity is promoted evidently. These factors may be identified as the primary reasons for its high de NOxactivity for NH3-SCR.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2015年第6期563-574,共12页
Journal of Molecular Catalysis(China)
基金
supported by the National Natural Science Foundation of China(No.21073131)
Shanxi Provincial Science and Technology Projects(No.20140313002-2)
State Key Laboratory Breeding Base of Coal Science and Technology Co-founded by Shanxi Province and the Ministry of Science and Technology
Taiyuan University of Technology(No.MKX201301)~~
