论文部分内容阅读
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.
The effects of preparation process on the structure, chemical composition and NH3-SCR activity of Mn-Fe / ZSM-5 catalyst were investigated by coprecipitation method and impregnation method, different iron precursors and different calcination temperatures. The results showed that when using The MFZ-CP-N-300 samples prepared by calcination at 300 ℃ showed the best catalytic activity at low temperature. The conversion of NO reached 96.7% at 120 ℃, The NO conversion in the range of 120 ~ 300 ℃ is always above 95%, and the chemical structure of the catalyst, crystal phase, acid sites, and ferromanganese oxide are also studied by XRD, NH3-TPD, XPS, SEM, TEM and nitrogen adsorption Morphology and surface morphology of the Mn-Mn oxides were characterized.The results show that the Mn-Mn oxides are highly dispersed on the catalyst surface in the form of Mn O2 -Mn2O3 and Fe2O3, respectively, especially when the Mn4 + / Mn3 + ratio is 1.254, Strong acid and more acid sites, thereby increasing the adsorption capacity of NH3, improve the conversion rate of NO.