Ceria promotion on the potassium resistance of MnOx/TiO2 SCR catalysts: An experimental and DFT study
Ceria promotion on the potassium resistance of MnOx/TiO2 SCR catalysts: An experimental and DFT study
复制标题
二氧化铈对 MnOx/TiO2 SCR 催化剂耐钾性的促进作用：实验和 DFT 研究
DOI：
10.1016/j.cej.2015.01.052
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发表时间：
2015-06-01
影响因子：
15.1
通讯作者：
Hao, Jiming
中科院分区：
文献类型：
--
作者：
Peng, Yue;Li, Junhua;Hao, Jiming
以NH3选择性催化还原(SCR)NO反应为研究对象，考察了催化剂K的失活和Ce2+对MnOx/TiO2催化剂活性的促进作用。K中毒是由于催化剂表面酸性降低，还原能力丧失，稳定的亚硝酸盐/硝酸盐物种增多所致。CeO2对催化剂进行改性后，无论是新鲜催化剂还是中毒催化剂的SCR活性都有所提高。Ce为NH3的吸附提供了新的Lewis酸位，这似乎不受K的影响，而中毒表面的Ce4f轨道几乎不受影响，这保持了催化剂对NH3活化的还原能力。稳定的、不活跃的亚硝酸盐物种不会积聚，活性硝酸盐物种仍然存在于表面。这些优势可以归因于独特的活性中心，[-0-Ce-O-Mn-0-](单位)。这些活性中心促使碱金属的运动聚集在一起，为SCR反应留下更多的表面活性中心。(C)2015爱思唯尔B.V.保留所有权利。
The deactivation of catalysts by potassium and the promotion of cerium on MnOx/TiO2 for selective catalytic reduction (SCR) of NO with NH3 are investigated by both experiments and OH calculations. Catalyst poisoning by K is due to the decrease of surface acidity, the loss of reducibility and the improvement of stable nitrite/nitrate species. When the catalyst is modified by CeO2, SCR activities of both fresh and poisoned catalysts are improved. Cerium provides new Lewis acid sites for NH3 adsorption, which does not seem to be influenced by K. The Ce 4f orbitals of poisoned surfaces are nearly unaffected, which preserve reducibility of catalyst for NH3 activation. Stable, inactive nitrite species do not build up and the reactive nitrate species are still present on the surface. These advantages can be attributed to the unique active sites, the [-0-Ce-O-Mn-0-](units). These active sites induce the movement of alkali metals to assemble together, leaving more surface active sites for SCR reaction. (C) 2015 Elsevier B.V. All rights reserved.