An in situ temperature dependent IR, EPR and high resolution XANES study on the NO/Cu+–ZSM-5 interaction

Prestipino, Carmelo; Berlier, Gloria; Xamena, Françesc X. Llabrés i; Spoto, G.; Bordiga, Silvia; Zecchina, Adriano; Palomino, Gemma Turnes; Yamamoto, Takashi; Lamberti, Carlo

doi:10.1016/s0009-2614(02)01183-1

Cited by 97 publications

(181 citation statements)

References 35 publications

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“…However, the heats of adsorption of the second NO molecule are only slightly higher at site III than at site II, because upon the first NO molecule adsorption on site II, Cu(I) ions are displaced to the position more resembling site III. Similarly, CO coordination on Cu + ions in ZSM-5 induces a displacement of copper ions, and the coordination of NO oxidizes Cu + ions as was observed [48].…”

Section: A Glimpse Into Opportunities and Issuessupporting

confidence: 57%

Environmental Catalysis over Zeolites

Centi¹,

Perathoner²

2010

Zeolites and Catalysis

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Section: A Glimpse Into Opportunities and Issuessupporting

confidence: 57%

Environmental Catalysis over Zeolites

Centi¹,

Perathoner²

2010

Zeolites and Catalysis

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“…and Cu 2? , respectively [37][38][39][40][41]. Figure 9b shows the FT-IR spectra of NO adsorbed on Cu-ZSM-5 zeolites with different metal loadings.…”

Section: Resultsmentioning

confidence: 99%

Cu-ZSM-5 Zeolites for the Formation of Methanol from Methane and Oxygen: Probing the Active Sites and Spectator Species

2010

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A series of Cu-ZSM-5 zeolites was prepared by varying nature of the charge compensating cation, copper precursor, copper loading, and pH. The materials were tested for the oxidation of methane to methanol using oxygen. A linear relationship between the amount of methanol produced over Cu-ZSM-5 zeolites from methane and oxygen and a UV-Vis-NIR DRS charge transfer band at 22,700 cm -1 is reported irrespective of the synthesis route used. The absolute intensity of the 22,700 cm -1 band is always low, indicating a low number of active sites in the samples. In all studied Cu-ZSM-5 zeolites at least two copper species were present: (a) Cu-O clusters dispersed on the outer surface of ZSM-5 and (b) highly dispersed copper-oxo species inside the channels, a minority fraction in the sample. By relating catalytic activity to FT-IR data of adsorbed pivalonitrile, visualizing Cu-O particles on the outer surface of the zeolite, and subsequently adsorbed NO, indicative of the Cu-O species inside the zeolite channel, it was concluded that Cu-O species on the outer surface are not involved in the oxidation reaction, while copper inside the channels are responsible for the selective conversion of methane to methanol.Keywords Methanol Á Methane activation Á Cu-ZSM-5 Á l-Oxo dicopper cluster Á UV-Vis spectroscopy Á FT-IR with pivalonitrile and NO

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“…Different probe molecules may be able to reveal different aspects of the investigated surface, and often the combined use of markedly different probes is the key for reaching a comprehensive understanding of the surface. 378,385,386 In the presence of an acceptor of electron pairs, such as a transition metal cation possessing empty orbitals of suitable energy (and thus acting as a Lewis acidic center), the C-end lone pair of CO is transferred to the metal cation, giving rise to a s-coordination (M n+ ' CO). 161,[375][376][377][378][379][380][381][382][383][384][385][386] The use of a weakly interacting probe such as N 2 allows the perturbation induced by the probe to be minimized and thus enables better discrimination between similar adsorption sites.…”

Section: Charge-balancing Extraframework Cationsmentioning

confidence: 99%

Probing zeolites by vibrational spectroscopies

et al. 2015

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This review addresses the most relevant aspects of vibrational spectroscopies (IR, Raman and INS) applied to zeolites and zeotype materials. Surface Brønsted and Lewis acidity and surface basicity are treated in detail. The role of probe molecules and the relevance of tuning both the proton affinity and the steric hindrance of the probe to fully understand and map the complex site population present inside microporous materials are critically discussed. A detailed description of the methods needed to precisely determine the IR absorption coefficients is given, making IR a quantitative technique. The thermodynamic parameters of the adsorption process that can be extracted from a variable-temperature IR study are described. Finally, cutting-edge space- and time-resolved experiments are reviewed. All aspects are discussed by reporting relevant examples. When available, the theoretical literature related to the reviewed experimental results is reported to support the interpretation of the vibrational spectra on an atomic level.

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An in situ temperature dependent IR, EPR and high resolution XANES study on the NO/Cu+–ZSM-5 interaction

Cited by 97 publications

References 35 publications

Environmental Catalysis over Zeolites

Environmental Catalysis over Zeolites

Cu-ZSM-5 Zeolites for the Formation of Methanol from Methane and Oxygen: Probing the Active Sites and Spectator Species

Probing zeolites by vibrational spectroscopies

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