Intermediates in the Reaction of NOxReduction with Propane over Cu/ZSM-5 Catalysts (by ESR, TPD, and IR-Spectroscopyin Situ)

Матышак, В. А.; Il’ichev, A. N.; Ukharsky, Anatoly A.; Корчак, В. Н.

doi:10.1006/jcat.1997.1766

Cited by 45 publications

(29 citation statements)

References 43 publications

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“…This suggests that optimum copper exchange occurs at lower concentrations of copper acetate (0.03 M). For overexchanged catalysts, the extra copper present in the catalysts is due to the formation of CuO clusters inside the pores and the catalyst surface [23].…”

Section: Acidity Measurementsmentioning

confidence: 99%

“…Metal cations located at different ion-exchange positions will have distinct stability as well as reactivity. Over the past few decades, several catalytic studies have been made using transition metal ion-exchanged porous solids and clays [19][20][21][22][23][24]. Recently, CuMCM-41 was reported for 1-butene isomerization and hydroxylation of phenol [25,26].…”

Section: Introductionmentioning

confidence: 99%

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Copper(II) ion exchanged AlSBA-15: A versatile catalyst for intermolecular hydroamination of terminal alkynes with aromatic amines

Shanbhag

Joseph

Halligudi

2007

Journal of Catalysis

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Section: Acidity Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Copper(II) ion exchanged AlSBA-15: A versatile catalyst for intermolecular hydroamination of terminal alkynes with aromatic amines

Shanbhag

Joseph

Halligudi

2007

Journal of Catalysis

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“…[23][24][25] This conclusion agree with ESR data for isolated Cu 2+ ions. 4,6,22,25 The intensive band in 30 000-32 000 cm -1 is identified as CTB L f M corresponding to square-plain oxide clusters. 24, 25 The origin of two bands 15 000-17 000 cm -1 and 18 000-23 000 cm -1 is not known and we assume that these bands are arising from copper oxide chain structures in zeolite channels.…”

Section: Quantum Chemical Model and Calculation Detailsmentioning

confidence: 99%

“…Stabilization of isolated Cu 2+ and Cu + ions, [4][5][6][7][8] as well as oxide CuO-and Cu 2 O-like clusters, 9,10 [22][23][24][25] in Cu-ZSM-5 has been observed by spectroscopic methods. These copper states each have been suggested to act as catalytic active sites in NO decomposition and SCR by hydrocarbons.…”

Section: Introductionmentioning

confidence: 99%

Density Functional Theory Molecular Cluster Study of Copper Interaction with Nitric Oxide Dimer in Cu−ZSM-5 Catalysts

et al. 2007

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The various quantum chemical models of catalytic active site in Cu-ZSM-5 zeolites are analyzed. The density functional theory (DFT) is used to calculate the electronic structure of molecular cluster (HO) 3 Al-O-Cu-O-Cu modeling the catalytic active site in Cu-ZSM-5 zeolites and study the interaction and decomposition of NO. It is assumed that the rate-determining stage of the low-temperature selective catalytic reduction of NO is the formation of the π-radical (N 2 O 2 ) -on electron donor sites of Cu-ZSM-5 catalysts. This is in good agreement with the high electron affinity of the molecular dimer ONNO (E a ) -1.5 eV) and is confirmed by the experimental data on the formation of surface anion π-radical (N 2 O 2 ) -on electron donor sites of supported organo-zirconium surface complex. The DFT calculated electronic structure and excitation energy spectra for the model system (HO) 3 Al-O-Cu-O-Cu show that it is a satisfactory model for description of experimental UV-vis spectra of Cu-ZSM-5, containing (-O-Cu-O-Cu-) chain structures in the zeolite channels. The calculated reaction energy profile of ONNO adsorption and decomposition on the model catalytic active site shows the possibility of the low-temperature decomposition of dimer (NO) 2 with low activation energy and the important role of copper oxide chains (-O-Cu-O-Cu-) in the channels of Cu-ZSM-5 zeolite during selective reduction of NO.

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“…The reactive surface species which are formed during the decomposition of NO and the selective catalytic reduction (SCR) of NO x on zeolites exchanged with copper have already been reviewed 9. The characteristic wavenumbers of these surface complexes can be obtained from the literature 28–39.…”

Section: Infrared Spectroscopymentioning

confidence: 99%

In situ IR, NMR, EPR, and UV/Vis Spectroscopy: Tools for New Insight into the Mechanisms of Heterogeneous Catalysis

Hunger

Weitkamp

2001

Angewandte Chemie Intl Edit

247

108

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The development of new solid catalysts for use in industrial chemistry has hitherto been based to a large extent upon the empirical testing of a wide range of different materials. In only a few exceptional cases has success been achieved in understanding the overall, usually very complex mechanism of the chemical reaction through the elucidation of individual intermediate aspects of a heterogeneously catalyzed reaction. With the modern approach of combinatorial catalysis it is now possible to prepare and test much more rapidly a wide range of different materials within a short time and thus find suitable catalysts or optimize their chemical composition. Our understanding of the mechanisms of reactions catalyzed by these materials must be developed, however, by spectroscopic investigations on working catalysts under conditions that are as close as possible to practice (temperature, partial pressures of the reactants, space velocity). This demands the development and the application of new techniques of in situ spectroscopy. This review will show how this objective is being achieved. By the term in situ (Lat.: in the original position) is meant the investigation of the chemical reactions which are taking place as well as the changes in the working catalysts directly in the spectrometer.

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Intermediates in the Reaction of NOxReduction with Propane over Cu/ZSM-5 Catalysts (by ESR, TPD, and IR-Spectroscopyin Situ)

Cited by 45 publications

References 43 publications

Copper(II) ion exchanged AlSBA-15: A versatile catalyst for intermolecular hydroamination of terminal alkynes with aromatic amines

Copper(II) ion exchanged AlSBA-15: A versatile catalyst for intermolecular hydroamination of terminal alkynes with aromatic amines

Density Functional Theory Molecular Cluster Study of Copper Interaction with Nitric Oxide Dimer in Cu−ZSM-5 Catalysts

In situ IR, NMR, EPR, and UV/Vis Spectroscopy: Tools for New Insight into the Mechanisms of Heterogeneous Catalysis

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