In-Situ XAFS, Photoluminescence, and IR Investigations of Copper Ions Included within Various Kinds of Zeolites. Structure of Cu(I) Ions and Their Interaction with CO Molecules

Yamashita, Hiromi; Matsuoka, Makoto; Tsuji, Kouji; Shioya, and Yasushi; Anpo, Masakazu; Che, Michel

doi:10.1021/jp952666z

Cited by 247 publications

(177 citation statements)

References 38 publications

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“…The majority of Cu + ions in ZSM-5 are expected to coordinate to two bridging oxygen atoms of the active site. 18,29,30,33,45,50,72 All structural parameters of our model, i.e., bond distances and the coordination number of the copper ion, are comparable to experimental results. Particularly, the calculated Cu-O bond distances of 2.013-2.032 Å (see Table 1) are in excellent agreement with the experimental data of 2.00 ( 0.02 Å, determined by Lamberti et al 8 In comparison with previous theoretical studies, our calculated Cu-O bond distances are slightly larger.…”

Section: Resultssupporting

confidence: 78%

Adsorption of Nitrogen Monoxide and Carbon Monoxide on Copper-Exchanged ZSM-5: A Cluster and Embedded Cluster Study

2001

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We present a systematic study on the adsorption of NO and CO in Cu-ZSM-5, using an ab initio embedded cluster methodology at the B3LYP level of theory. We found that the effects of the cluster size and Madelung potential are small for adsorption energies of CO and NO. For adsorption of CO, the calculated binding energy of 32 kcal/mol is in good agreement with experimental data from 29 to 32 kcal/mol. On the contrary, for adsorption of NO the calculated binding energy of 22 kcal/mol is much smaller than the experimental estimate, though it is consistent with recent experimental observation that NO binding energy should be smaller than that of CO. Madelung potential, however, is important for obtaining the correct blue shift of an adsorbed CO and red shift of an adsorbed NO.

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Section: Resultssupporting

confidence: 78%

Adsorption of Nitrogen Monoxide and Carbon Monoxide on Copper-Exchanged ZSM-5: A Cluster and Embedded Cluster Study

2001

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“…The latter spectrum consists of a broad intense band with maximum absorbance at 33,400 cm −1 . Previous studies [58,59] have attributed the absorption bands at around 35,700-33,300, and 33,300-31,200 cm −1 to the electronic excitation of the Cu + ion (3d 10 → 3d 9 4s 1 ) and the Cu + Cu + dimer (3σ * → 3σ ) respectively. As a result, the observed 33,400 cm −1 band can be explained by the presence of Cu + monomers, Cu + Cu + dimers, or a mixture of them.…”

Section: Time and Temperature Dependence Of The No Decompositionmentioning

confidence: 99%

An operando optical fiber UV–vis spectroscopic study of the catalytic decomposition of NO and N2O over Cu-ZSM-5

Groothaert

Lievens

Leeman

et al. 2003

Journal of Catalysis

131

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The role of the bis(µ-oxo)dicopper core, i.e., [Cu 2 (µ-O) 2 ] 2+ , in the decomposition of NO and N 2 O by the Cu-ZSM-5 zeolite has been studied with combined operando UV-vis monitoring of the catalyst and on-line GC analysis. An optical fiber was mounted on the outer surface of the quartz wall of the plug-flow reactor and collected the UV-vis diffuse reflectance spectra under true catalytic conditions.

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“…[79,80] Determination of the Cu oxidation state, coordination number and CuϪO bond lengths can be achieved by X-ray absorption fine structure (XAFS) techniques. [81,82] However, for isolated Cu II sites the EXAFS (extended X-ray absorption fine structure) spectrum only yields average CuϪO bond lengths and coordination numbers. Hence, this technique is not well suited to offer detailed information on the different Cu II sites and is more often used to distinguish between isolated versus clustered Cu ions in over-exchanged zeolites.…”

Section: Additional Observationsmentioning

confidence: 99%

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

Delabie

Pierloot

Groothaert

et al. 2002

Eur. J. Inorg. Chem.

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Keywords: Zeolites / Copper / Ab initio calculations / Density functional calculations / ESR spectroscopy / UV/Vis spectroscopy / Heterogeneous catalysis Zeolites loaded with transition metal ions are promising heterogeneous catalysts. Knowledge about the location and structure of the metal centers is of paramount importance for the understanding of the catalytic potential of these materials. In this work, the spectroscopic studies of the coordination of Cu II in zeolite A, ZK4, X, Y and mordenite are reviewed. Experimentally, diffuse reflectance spectroscopy [a] teaches general chemistry and computational chemistry. Her main research interest is the application of ab initio methods for the study of spectroscopic and magnetic properties of systems containing transition metals. Marijke H. Groothaert (left center) was born in Neerpelt, Belgium in 1975. In 1998 she received her M. S. degree from the . Since 1998 she is a PhD student at the Center for Surface Chemistry and Catalysis under the supervision of Professor Robert A. Schoonheydt. Her research is concentrated on the coordination of transition metal ions in zeolites and combines spectroscopic techniques with computational methods. Robert A. Schoonheydt (left bottom) received his M. S. degree in 1966 and . Hab. in Leuven, where he teaches quantum chemistry, computational chemistry, and inorganic chemistry. His main research interests are in the application of computational methods in different areas of chemistry.MICROREVIEWS: This feature introduces the readers to the authors' research through a concise overview of the selected topic. Reference to important work from others in the field is included. 515(DRS) and electron spin resonance (ESR) spectroscopy have been applied to study the coordination of Cu II in zeolites. Ab initio calculations on model clusters, representing the Cu II sites in zeolites, are used for the interpretation of the experimental data. The combination of experimental spectroscopic information with theoretical results leads to a new and profound insight into the Cu II −zeolite interaction.

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In-Situ XAFS, Photoluminescence, and IR Investigations of Copper Ions Included within Various Kinds of Zeolites. Structure of Cu(I) Ions and Their Interaction with CO Molecules

Cited by 247 publications

References 38 publications

Adsorption of Nitrogen Monoxide and Carbon Monoxide on Copper-Exchanged ZSM-5: A Cluster and Embedded Cluster Study

Adsorption of Nitrogen Monoxide and Carbon Monoxide on Copper-Exchanged ZSM-5: A Cluster and Embedded Cluster Study

An operando optical fiber UV–vis spectroscopic study of the catalytic decomposition of NO and N2O over Cu-ZSM-5

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

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