从EPR谱图(图2)可以看出,Cu/SSZ-13和CuMn(0.6)/SSZ-13具有相似的EPR信号(g∥为2.386−2.392,A∥为134−137 G),表明两种催化剂中孤立Cu2+分布在cha笼内的相同位置。CuMn(0.6)/SSZ-13的EPR信号更强(内插图)则说明其...
采用微波辐射法和传统水热法分别制备了Cu-SSZ-13催化剂,用于柴油车尾气NOx的脱除.用X射线衍射(XRD),N2物理吸脱附,H2程序升温还原(H2-TPR),电子顺磁共振(EPR),NH3程序升温脱附(NH3-TPD),电感耦合等离子体质谱(ICP-MS)及X射线光电子能谱(XPS)等方法对样品进行表征.结果表明,微波辐射法大大缩短了SSZ-13分子...
五、【成果启示】 研究通过详细比较了商业Cu/SSZ-13催化剂在加速实验室老化和现实环境老化的各项数据,阐明了这两种方法之间的差距。采用多种催化剂表征方法,包括比表面积/孔隙率分析,X射线衍射(XRD),H2-温度程序还原,NH3-温度程序解吸,固体核磁(NMR),原位X射线光电子(XPS)和电子顺磁共振(EPR)谱,将由此获得的Cu...
Cu-SSZ-13在TA作用下发生活性损失。由于分离出的Cu2+是催化SCR反应的活性位点,活性下降应与Cu2+离子在TA作用下向其他SCR活性位点CuO和CuAl2O4的转化有关,如EPR(图5)、H2-TPR(图6)和TEM(图7)结果所示。Cu-TA-750和Cu-TA...
Fig. 1 presents EPR results of the Cu-SSZ-13 samples at room temperature. These samples were cooled to room temperature in air after calcination during which they adsorbed moisture and, therefore, are defined as hydrated samples. In these samples, Cu species should all be present as EPR activ...
EPR, H 2 -TPR, NH 3 -TPD, NMR were utilized to determine that the Brnsted acid sites were modified while the Cu species remained unchanged. Thereby an accurate assessment of the influence of Brnsted acid sites on N 2 O formation could be achieved. Our results showed that Cu-SSZ-13 ...
XPS与31P固体核磁表明长链和缩聚磷物种受到水分子的攻击,裂解成短链和缩聚较少的磷物种,此外,结合H2-TPR、XPS、NO-DRIFTS以及EPR分析,证实了再生过程中有部分铜磷酸盐/偏磷酸盐/氧化磷溶解在热水中,Cu-SSZ-13对NO的吸附能力增强,活性Cu2+含量也随着洗涤时间延长而变多。
(1)对于分子筛基SCR催化剂来说,调整活性组分的位置会影响其反应活性。 (3)EPR技术可以确认Cu2+在SCR催化剂中的配位环境。 Chen Z., et al.Controllable p…
EPRin situ spectroscopyCu/SSZ-13 selective catalytic reduction catalysts display activity loss after mild hydrothermal aging without support degradation or loss of isolated Cu cation content. By applying electron paramagnetic resonance spectroscopy to compare hydrated, dehydrated, and NH3-saturated catalysts ...
Nevertheless, the quantification of the different Cu2+ ions results challenging, typically relying on signals deconvolution affected by the overlap of multiple peaks and/or by the selection of reference spectra (NH3-TPD, H2-TPR, XANES, EPR) [5], [18], [23], [30], [31]. In this context...