微型多孔材料
沸石
选择性催化还原
催化作用
反应性(心理学)
氮氧化物
化学
动力学
离子
无机化学
氧化还原
从头算
X射线吸收光谱法
反应速率常数
物理化学
吸收光谱法
有机化学
病理
物理
燃烧
医学
替代医学
量子力学
作者
Mykela DeLuca,Casey B. Jones,Siddarth H. Krishna,Anshuman Goswami,Raghav Saxena,Sichi Li,Subramanian Prasad,Ahmad Moini,William F. Schneider,Rajamani Gounder
出处
期刊:Chem catalysis
[Elsevier]
日期:2023-08-16
卷期号:3 (9): 100726-100726
被引量:8
标识
DOI:10.1016/j.checat.2023.100726
摘要
The low-temperature (<523 K) selective catalytic reduction (SCR) of nitrogen oxides proceeds on Cu-zeolites. Cu cations are NH3 solvated, ionically tethered to framework Al centers, and partially mobile within microporous voids, influencing the ability of Cu ions to pair within voids to close the SCR oxidation half-cycle. The influence of zeolite framework topological features on pairability and Cu-normalized SCR reactivity is not well understood. We combine steady-state kinetics and operando and transient X-ray absorption (XAS) measurements on Cu-zeolites chosen to probe the influence of pore structure and dimensionality on SCR rate constants and fractions of SCR-active Cu sites, together with statistical simulations and ab initio dynamics simulations, to show that changes in pore size and shape among 3D cage-window zeolites have subtle effects on Cu ion pairability and SCR reactivity but that decreasing pore dimensionality to 2D or 1D networks imposes more severe restrictions on Cu ion pairability and SCR reactivity.
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