Effects of alkali and alkaline earth metals on Cu-SSZ-39 catalyst for the selective catalytic reduction of NOx with NH3
Effects of alkali and alkaline earth metals on Cu-SSZ-39 catalyst for the selective catalytic reduction of NOx with NH3
复制标题
碱金属和碱土金属对 Cu-SSZ-39 催化剂用于 NH3 选择性催化还原 NOx 的影响
DOI：
10.1016/j.cej.2020.124250
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发表时间：
2020
影响因子：
15.1
通讯作者：
He Hong
中科院分区：
文献类型：
--
作者：
Zhu Na;Shan Wenpo;Shan Yulong;Du Jinpeng;Lian Zhihua;Zhang Yan;He Hong
尿素溶液和发动机润滑油中的碱/碱土金属会导致 NH3-SCR 催化剂化学失活。 Cu-SSZ-39具有优异的催化性能和水热稳定性，被认为是柴油车氮氧化物减排的良好选择。在这项工作中，首次研究了碱金属/碱土金属对 Cu-SSZ-39 的影响。碱金属/碱土金属的失活效果顺序为 K > Mg > Ca > Na。引入碱金属/碱土金属后，表面积、孤立的Cu2+离子和酸位大大减少。在相同负载量（1 mmol/克催化剂）下，Na 和 K 对沸石表面酸度的影响比 Ca 和 Mg 更大。在每种碱金属/碱土金属中毒后，观察到沸石结构的恶化以及孤立的Cu 2+ 离子向CuO x 的转变。铜物种的分布是决定Cu-SSZ-39碱/碱土金属中毒后SCR性能的一个非常重要的因素。这项工作为理解铜基小孔沸石的失活机制提供了新的见解。
Alkali/alkaline earth metals from urea solution and engine lubricating oil can induce the chemical deactivation of NH3-SCR catalysts. Cu-SSZ-39, with excellent catalytic performance and hydrothermal stability, is thought to be a good choice for the NOxabatement from diesel vehicles. In this work, the effects of alkali/alkaline earth metals on Cu-SSZ-39 were investigated for the first time. The deactivation effects of alkali/alkaline earth metals followed the order of K > Mg > Ca > Na. The surface area, isolated Cu2+ions and acid sites greatly decreased after the introduction of alkali/alkaline earth metals. Na and K had greater influence on the zeolite surface acidity than Ca and Mg with the same loading amount (1 mmol per gram catalyst). The deterioration of the zeolite structure and the transformation of isolated Cu2+ions to CuOxwere observed after poisoning by each of the alkali/alkaline earth metals. The distribution of copper species is a very important factor determining the SCR performance of Cu-SSZ-39 after alkali/alkaline earth metals poisoning. This work provides a new insight into understanding deactivation mechanisms in Cu-based small-pore zeolites.