Removal of nitrogen monoxide through a novel catalytic process. 1. Decomposition on excessively copper-ion-exchanged ZSM-5 zeolites

Iwamoto, Masakazu; Yahiro, Hidenori; Tanda, Kenji; Mizuno, Noritaka; Mine, Yosihiro; Kagawa, Shuichi

doi:10.1021/j100162a053

Cited by 562 publications

(298 citation statements)

References 5 publications

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“…At 673-773 K, a 38-77% N 2 yield is found for a 1 mol% NO feed, while no N 2 O yield is detected. Below 673 K, the N 2 O yield rapidly increases and exceeds the N 2 yield at 623 K. This finding is in accordance with previous studies, which inferred that N 2 O is an intermediate in the NO decomposition cycle [23,40,43,45]. Studying the N 2 O decomposition activity as function of the temperature (Fig.…”

Section: Bis(µ-oxo)dicopper Formed By O Abstraction Of N 2 Osupporting

confidence: 91%

“…Additional catalytic results of this CZ-31-0.58 sample and of a sample with Si/Al = 12 can be found in a recent contribution of our group [49] where also the effluent NO and NO 2 concentrations were monitored using a NO x analyzer. In the latter study, a 100% selective NO decomposition to O 2 and N 2 was obtained for a 0.1 mol% NO in He flow (GHSV of 900 h −1 ) in the temperature range from 773 to 723 K. The catalytic results of our Cu-ZSM-5 samples are in agreement with the literature data [21,23,40]. New information is obtained with the concomitant UV-vis monitoring.…”

Section: Time and Temperature Dependence Of The No Decompositionsupporting

confidence: 88%

“…6a and 6b show that the N 2 and O 2 yields (1) are low for the samples with Cu/Al ratios of 0.10 and 0.22, (2) sharply increase for the Cu/Al 0.31 sample, and (3) further increase for the higher Cu/Al ratios. In 1991, Iwamoto et al [23] were the first to report this sharp increase in activity for samples with Cu/Al > 0.2. In order to estimate the amount of bis(µ-oxo)dicopper in the CZ-12 series of samples, the UV-vis-NIR spectra were collected after calcination and are shown in Fig.…”

Section: No Decomposition Activity As a Function Of The Copper Contenmentioning

confidence: 97%

“…A 100% selective conversion of NO into N 2 and O 2 can be achieved over Cu-ZSM-5 above 623 K with maximum activity in the temperature range 723-773 K [21]. Several explanations for this profile have been proposed, such as (1) the desorption of oxygen [21], (2) the instability or surface nitrates [22], and (3) the adsorption equilibrium of NO [23]. Li and Hall [24] suggested that the NO 2 production observed in case of incomplete NO decomposition results from the reaction of NO with produced O 2 in the cool exit zone of the reactor.…”

Section: Introductionmentioning

confidence: 99%

“…This EPR silent copper fraction took our attention since the NO decomposition activity has a S-shaped dependence on the copper exchange level in ZSM-5 [15,21,23]. The NO decomposition rate gradually increases for the lower exchange levels and increases sharply above the Cu/Al ratio of 0.2 [23]. Therefore, we applied XAFS and UV-vis-NIR spectroscopy to identify the large fraction of EPR silent copper (81% of the total Cu content) in the calcined overexchanged Cu-ZSM-5 (Cu/Al = 0.6).…”

Section: Introductionmentioning

confidence: 99%

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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

138

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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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Section: Bis(µ-oxo)dicopper Formed By O Abstraction Of N 2 Osupporting

confidence: 91%

Section: Time and Temperature Dependence Of The No Decompositionsupporting

confidence: 88%

Section: No Decomposition Activity As a Function Of The Copper Contenmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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

138

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Catalytic control of automotive NOx: a review

Bhattacharyya¹,

Das²

1999

Int. J. Energy Res.

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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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Removal of nitrogen monoxide through a novel catalytic process. 1. Decomposition on excessively copper-ion-exchanged ZSM-5 zeolites

Cited by 562 publications

References 5 publications

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

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

Catalytic control of automotive NOx: a review

The Coordination of CuII in Zeolites − Structure and Spectroscopic Properties

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