Ce-Ti Amorphous Oxides for Selective Catalytic Reduction of NO with NH3: Confirmation of Ce-O-Ti Active Sites
Ce-Ti Amorphous Oxides for Selective Catalytic Reduction of NO with NH3: Confirmation of Ce-O-Ti Active Sites
复制标题
Ce-Ti 无定形氧化物用于 NH3 选择性催化还原 NO：Ce-O-Ti 活性位点的确认
DOI：
10.1021/es301661r
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发表时间：
2012-09-04
影响因子：
11.4
通讯作者：
Zheng, Lirong
中科院分区：
文献类型：
--
作者：
Li, Ping;Xin, Ying;Zheng, Lirong
无定形Ce-Ti混合氧化物被报道是用于用NH3选择性催化还原NOx的催化剂，其中Ce而不是Ti作为它们的溶剂，尽管事实上Ce含量低。采用X射线粉末衍射（XRD）和透射电子显微镜（TEM）结合选区电子衍射（SAED）对催化剂进行了表征。Ce-Ti非晶态氧化物在较低温度下比其晶态对应物显示出更高的活性。此外，对于浸渍样品，小CeO 2微晶的存在对活性有害。通过程序升温还原（H-2-TPR）、原位红外光谱（FTIR）、X射线光电子能谱（XPS）和X射线吸收精细结构（XAFS）等方法，首次证实了Ce-O-Ti短程有序物种是催化剂的活性中心，其中Ce和Ti之间存在原子尺度的相互作用。最后，通过场发射透射电镜（FETEM）直接观察到Ce-O-Ti结构。
The amorphous Ce-Ti mixed oxides were reported to be catalysts for selective catalytic reduction of NOx with NH3, in which Ce and not Ti acts as their solvent in spite of the fact that Ce is low in content. The amorphous catalysts were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) equipped with selective area electron diffraction (SAED). The Ce-Ti amorphous oxide shows higher activity than its crystalline counterpart at lower temperatures. Moreover, the presence of small CeO2 crystallites as for the impregnated sample is deleterious to activity. The Ce-O-Ti short-range order species with the interaction between Ce and Ti in atomic scale was confirmed for the first time to be the active site using temperature programmed reduction with H-2 (H-2-TPR), in situ FTIR spectra of NO adsorption, X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine-structure (XAFS). Lastly, the Ce-O-Ti structure was directly observed by field-emission TEM (FETEM).