Highly dispersed surface active species of Mn/Ce/TiW catalysts for high performance at low temperature NH3-SCR
Highly dispersed surface active species of Mn/Ce/TiW catalysts for high performance at low temperature NH3-SCR
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Mn/Ce/TiW 催化剂的高度分散表面活性物质，可实现低温高性能 NH3-SCR
DOI：
10.1016/j.cej.2017.08.069
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发表时间：
2017-12-15
影响因子：
15.1
通讯作者：
Liu, Xuesong
中科院分区：
文献类型：
--
作者：
Chen, Hongfeng;Xia, Yang;Liu, Xuesong
本文采用共沉淀法（C-Mn/Ce/TiW）、共沉淀-混合法（CM-Mn/Ce/TiW）和混合法（M-Mn/Ce/TiW）制备了Mn/Ce/TiW催化剂。结果表明，C-Mn/Ce/TiW样品在180 ℃和210 ℃的低温下分别表现出90%和99.4%的最高NOx转化率。这种NOx转化率的提高可以归因于在整个温度范围内作为活性中心的表面活性物种的增加，例如Ce 3+（19.55%）、Mn 4+（59.58%）和化学吸附氧物种（21.89%）。这些表面活性物种主要来自高度分散的CeOx和MnO 2。结果表明，催化剂的物相和织构性质对催化活性的影响不大。随着分散度和表面活性物质含量的增加，催化剂的酸性和还原性沿着增强，是SCR反应性能提高的主要原因。这些基础研究结果将有助于合理设计高性能的低温SCR催化剂。
In this work, Mn/Ce/TiW catalysts were prepared by various synthetic strategies including coprecipitation method (named as C-Mn/Ce/TiW), coprecipitation-mixing method (CM-Mn/Ce/TiW) and mixing method (M-Mn/Ce/TiW). As a result, C-Mn/Ce/TiW sample exhibited the highest NOx conversion of 90% and 99.4% at the low temperatures of 180 degrees C and 210 degrees C, respectively. This enhanced NOx conversion can be attributed to the increased surface active species served as active sites within the whole temperature range, such as Ce3+ (19.55%), Mn4+ (59.58%) and chemisorbed oxygen species (21.89%). These surface active species originated mainly from the highly dispersed CeOx and MnO2. The results revealed that the influences of the phase and texture property on catalytic activity were slight. And the gradually enhanced acidity and reducibility along with the dispersion degrees and the amount of surface active species were the main reasons for the improvement of SCR reaction. These fundamental findings will be helpful for the rational design of high-performance SCR catalysts at the low temperature.