Theoretical Study of Cu<sup>I</sup>Y Zeolite:  Structure and Electronic Properties

Jardillier, Nicolas; Berthomieu, and Dorothée; Goursot, Annick; and, J. Ulises Reveles; Köster, Andreas M.

doi:10.1021/jp063568o

Cited by 9 publications

(11 citation statements)

References 38 publications

(71 reference statements)

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“…Let us first consider the bare Cu(I)-containing zeolite without adsorbed O 2 (for a discussion of the oxidation state of copper, see section 5.3). In agreement with the computational results of Sierka, Sauer and co-workers 18 and Jardillier et al, 63 with only one Al atom per ring, the Cu(I) ion is coordinated to 3 or 2 oxygen atoms for adsorption sites II and III, respectively. These O atoms are of type O2 in the case of the SII adsorption site, i.e.…”

Section: Cluster Modelssupporting

confidence: 91%

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Adsorption of dioxygen to copper in CuHY zeolite

Santra

Archipov

Ene

et al. 2009

Phys. Chem. Chem. Phys.

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The adsorption of dioxygen to copper in CuHY zeolites has been studied by means of FTIR spectroscopy and model calculations at the quantum mechanical/molecular mechanics (QM/MM) level. Different Si/Al ratios, substitution patterns and adsorption sites within the cavities of the zeolite lead to a large number of different isomers to be studied. In addition, these parameters control the end-on vs. side-on adsorption of dioxygen. High-level multireference benchmark calculations for the singlet and triplet states of such adsorption complexes corroborate the use of density functional theory for the investigation of these systems. Comparison of the experimental and computed data allows for the identification of a preferred adsorption site and a small number of isomers which appear to be most relevant for the adsorption process. Redshifts of >250 cm(-1) are obtained for the vibrational frequencies of adsorbed O(2).

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Section: Cluster Modelssupporting

confidence: 91%

“…A QM region which is too small may result in artifacts. Consequently, rather large QM regions have been suggested by other authors, 18,63 but usually at the cost of the quality of the basis set. For this very reason, we performed systematic calculations with different QM regions.…”

Section: Qm/mm Calculations Vs Molecular Fragment Calculationsmentioning

confidence: 99%

Adsorption of dioxygen to copper in CuHY zeolite

Santra

Archipov

Ene

et al. 2009

Phys. Chem. Chem. Phys.

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“…Experiments were performed under various conditions and for zeolites prepared in different ways, thus results can differ in details. Similar results have been obtained by Jardillier et al, 42 who also have found Cu(I) only within the 6T ring plane. Our results, showing site III significantly less stable (about 100 kJ mol À1 ) than sites II and I 0 (Table 5), agree with these observations.…”

Section: Cu(i) Sitingsupporting

confidence: 90%

“…The QM-Pot approach is particularly useful for extended systems such as zeolites. 29 Previous computational studies on the Cu(I)-FAU system used free cluster models [39][40][41][42][43][44][45] and did not lead to a reliable assignment of CO stretching frequencies. The QM-Pot method gives more reliable results than free cluster models and is computationally less demanding than periodic quantum mechanical calculations.…”

Section: Introductionmentioning

confidence: 99%

Theoretical studies of Cu(i) sites in faujasite and their interaction with carbon monoxide

Rejmak

Sierka

Sauer

2007

Phys. Chem. Chem. Phys.

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Sitting, coordination, and properties of Cu(I) cations in zeolite faujasite are investigated using a combined quantum mechanics-interatomic potential function method. The coordination of Cu(I) ions depends on their location within the zeolite lattice. Cu(I) located inside the hexagonal prisms (site I') and in the plane of six-membered aluminosilicate rings on the walls of sodalite units (site II) is threefold coordinated, whereas Cu(I) located in the supercages (site III) is twofold coordinated. In agreement with available experimental data Cu(I) appears to be more strongly bound in sites I' and II than in site III. The binding energy of site II Cu(I) ions increases with the number of Al atoms, but only closest Al atoms have a substantial influence. The CO molecule binds more strongly onto sites with weaker bound cations and lower coordination. We assign the two CO stretching IR bands observed for Cu(I)-Y zeolites to sites II with one Al (2157-2161 cm(-1)) and two Al atoms (2140-2148 cm(-1)) in the six-membered aluminosilicate ring. For Cu(I)-X we tentatively assign the high frequency band to site III (2156-2168 cm(-1)) and the low-frequency band to site II with three Al atoms in the six-membered ring (2136-2138 cm(-1)).

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“…Using tetrahedral coordinates that have already been determined by various experiments, a reasonable model can be built to simulate the zeolite framework. Because the location and distribution of heteroatoms in the framework are connected to the structural properties of zeolites, theoretical studies give a better understanding of the nature of isomorphically substituted zeolites [33,34].…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of Zirconium Isomorphous Substitution into Zeolite Frameworks

Xing

Wang

et al. 2019

Molecules

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Systematic periodic density functional theory computations including dispersion correction (DFT-D) were carried out to determine the preferred location site of Zr atoms in sodalite (SOD) and CHA-type topology frameworks, including alumino-phosphate-34 (AlPO-34) and silico-alumino-phosphate-34 (SAPO-34), and to determine the relative stability and Brönsted acidity of Zr-substituted forms of SOD, AlPO-34, and SAPO-34. Mono and multiple Zr atom substitutions were considered. The Zr substitution causes obvious structural distortion because of the larger atomic radius of Zr than that of Si, however, Zr-substituted forms of zeolites are found to be more stable than pristine zeolites. Our results demonstrate that in the most stable configurations, the preferred favorable substitutions of Zr in substituted SOD have Zr located at the neighboring sites of the Al-substituted site. However, in the AlPO-34 and SAPO-34 frameworks, the Zr atoms are more easily distributed in a dispersed form, rather than being centralized. Brönsted acidity of substituted zeolites strongly depends on Zr content. For SOD, substitution of Zr atoms reduces Brönsted acidity. However, for Zr-substituted forms of AlPO-34 and SAPO-34, Brönsted acidity of the Zr-O(H)-Al acid sites are, at first, reduced and, then, the presence of Zr atoms substantially increased Brönsted acidity of the Zr-O(H)-Al acid site. The results in the SAPO-34-Zr indicate that more Zr atoms substantially increase Brönsted acidity of the Si-O(H)-Al acid site. It is suggested that substituted heteroatoms play an important role in regulating and controlling structural stability and Brönsted acidity of zeolites.

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Theoretical Study of Cu^IY Zeolite: Structure and Electronic Properties

Cited by 9 publications

References 38 publications

Adsorption of dioxygen to copper in CuHY zeolite

Adsorption of dioxygen to copper in CuHY zeolite

Theoretical studies of Cu(i) sites in faujasite and their interaction with carbon monoxide

Theoretical Study of Zirconium Isomorphous Substitution into Zeolite Frameworks

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Theoretical Study of CuIY Zeolite: Structure and Electronic Properties

Cited by 9 publications

References 38 publications

Adsorption of dioxygen to copper in CuHY zeolite

Adsorption of dioxygen to copper in CuHY zeolite

Theoretical studies of Cu(i) sites in faujasite and their interaction with carbon monoxide

Theoretical Study of Zirconium Isomorphous Substitution into Zeolite Frameworks

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Theoretical Study of Cu^IY Zeolite: Structure and Electronic Properties