Mapping Vibrational Spectra to the Structures of Copper Species in Zeolites Based on Calculated Stretching Frequencies of Adsorbed Nitrogen and Carbon Monoxides
Mapping Vibrational Spectra to the Structures of Copper Species in Zeolites Based on Calculated Stretching Frequencies of Adsorbed Nitrogen and Carbon Monoxides
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基于计算的吸附氮和一氧化碳的拉伸频率将振动光谱映射到沸石中铜物质的结构
DOI：
10.1021/acs.jpcc.1c01649
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
J. V. van Bokhoven
中科院分区：
文献类型：
--
作者：
D. Palagin;V. Sushkevich;Amy J. Knorpp;M. Ranocchiari;J. V. van Bokhoven
在这项工作中，吸附一氧化氮和一氧化碳探针分子上的各种铜网站在一系列的沸石进行了研究。用密度泛函理论计算了铜离子的结构、探针分子的结合能和振动频率。这允许将振动光谱区域映射到作为沸石拓扑结构和Si/Al比的函数的特定铜物质。一氧化碳可以通过形成单羰基和二羰基吸附在Cu +离子上，或者通过形成甲氧基-单羰基吸附在与甲氧基物质键合的铜离子上，其表现出波数的蓝移。吸附NO的伸缩振动频率一般按以下顺序增加：[CuOH] + < [Cu 2 O] 2+ /[Cu 2 O2] 2+ < [Cu 2+ ] < [Cun +1 On] 2+ /[CunOn] 2+（n >3）< [Cu 3 O2] 2+ /[Cu 3 O3] 2+。不同物种间的位移值在5 ~ 20 cm-1之间，表明基于红外频率进行结构归属的可能性。具有较小孔的沸石框架表现出吸附的一氧化氮的振动带向较低的频率移动，由于沸石孔结构的限制效应。具有较大孔隙的沸石稳定较高核性的铜物种。我们的数据表明，表列的吸附碳和一氧化氮的红外频率可用于分配沸石铜形态，
: In this work, adsorption of nitrogen monoxide and carbon monoxide probe molecules on various copper sites in a range of zeolites is studied. Structures of copper sites, binding energies and vibrational frequencies of adsorbed probe molecules are calculated by density functional theory. This allows mapping vibrational spectra regions to specific copper species as a function of the zeolite topology and Si/Al ratio. Carbon monoxide can adsorb on Cu + ions by forming mono-and dicarbonyls, or on copper ions bonded to methoxy species by forming methoxy-monocarbonyls, which exhibit a blue shift in wavenumbers. The stretching frequencies of adsorbed nitrogen monoxide generally increase in the following order: [CuOH] + < [Cu 2 O] 2+ /[Cu 2 O 2 ] 2+ < [Cu 2+ ] < [Cu n +1 O n ] 2+ /[Cu n O n ] 2+ ( n >3) < [Cu 3 O 2 ] 2+ /[Cu 3 O 3 ] 2+ . The shift values between different species vary between 5 and 20 cm –1 , showing the possibility for structure assignment based on infrared frequencies. Zeolite frameworks with smaller pores exhibit a shift of vibrational bands of adsorbed nitrogen monoxide towards lower frequencies, due to a confinement effect of zeolite pore structure. Zeolites with larger pores stabilize copper species of higher nuclearity. Our data indicate that tabulated infrared frequencies of adsorbed carbon and nitrogen monoxides may be used to assign zeolitic copper speciation from
影响因子：
62.1
作者：
Solomon, Edward I.;Heppner, David E.;Johnston, Esther M.;Ginsbach, Jake W.;Cirera, Jordi;Qayyum, Munzarin;Kieber-Emmons, Matthew T.;Kjaergaard, Christian H.;Hadt, Ryan G.;Tian, Li
通讯作者：
Tian, Li
影响因子：
4.9
作者：
Beale, A. M.;Lezcano-Gonzalez, I.;Wragg, D. S.
通讯作者：
Wragg, D. S.