Cu(I)-ZSM-5 zeolites prepared by reaction of H-ZSM-5 with gaseous CuCl: Spectroscopic characterization and reactivity towards carbon monoxide and nitric oxide

Spoto, G.; Zecchina, Adriano; Bordiga, Silvia; Ricchiardi, Gabriele; Martra, Gianmario; Leofanti, G.; Petrini, G.

doi:10.1016/0926-3373(93)e0032-7

Cited by 284 publications

(371 citation statements)

References 21 publications

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“…2, spectra b-o). Taking into account the results obtained after adsorption of CO, and the 12 CO-13 CO isotopic shift factor (0.97777) we assign the above bands as follows: 2214 cm À1 , to Mn 2þ -12 CO; 2202 cm À1 , to the mð 12 C-OÞ stretches of Mn 2þ ðCOÞ x species; 2175 cm À1 , to OH-12 CO; 2165 cm À1 , to Mn 2þ - 13 CO with participation of some OH-CO vibrations; 2152 cm À1 , to the mð 13 C-OÞ modes of Mn 2þ ðCOÞ x species; 2139 cm À1 , to physically adsorbed 12 CO; 2127 cm À1 , to OH-13 CO; and 2092 cm À1 , to physically adsorbed 13 CO. The band at 2075 cm À1 arises from H-bonded 13 C 18 O.…”

Section: Coadsorption 12 Co and 13 Co On Mn-zsm-5mentioning

confidence: 99%

“…The most typical examples are the formation of Ag þ ðCOÞ 2 species with Ag-ZSM-5 [12]; Cu 2þ ðCOÞ 2 and Cu þ ðCOÞ 3 species with Cu-ZSM-5 [13][14][15]; and Ni 2þ ðCOÞ 2 and Ni þ ðCOÞ 3 species with Ni-ZSM-5 [16]. The latter two cases indicate, once again, that the process is favoured by a big cationic radius: decreasing oxidation state of the cation is accompanied by an increase of its ionic radius so that even three molecules can be coordinated simultaneously to one cation provided its radius is sufficiently large.…”

Section: Introductionmentioning

confidence: 99%

“…In these cases, however, the polycarbonyls are normally decomposed without passing through linear species. During the past years a new class of geminal species (the so-called site-specified geminal species [1]) was discovered [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. All these species are formed on metal-exchanged zeolites or on related materials and are decomposed losing their ligands stepwise.…”

Section: Introductionmentioning

confidence: 99%

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FTIR study of low-temperature CO adsorption on Mn-ZSM-5 and MnY zeolites. Effect of the zeolite matrix on the formation of Mn2+(CO) geminal species

Hadjiivanov

Ivanova

Kantcheva

et al. 2002

Catalysis Communications

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Adsorption of CO on Mn-ZSM-5 zeolite at 85 K results in formation of physically adsorbed CO, several kinds of Hbonded CO and Mn 2þ ðCOÞ x geminal species ð2202 cm À1 Þ. Decreasing the coverage during evacuation results in disappearance of the physically adsorbed CO and the H-bonded forms and in conversion of the dicarbonyls to linear Mn 2þ -CO species ð2214 cm À1 Þ. The latter are quite stable at 85 K. Coadsorption 12 CO and 13 CO reveals that the CO molecules in the geminal polycarbonyls behave as independent oscillators. In contrast, CO adsorption at 85 K on MnNaY zeolite only leads to formation of linear Mn 2þ -CO species (2210 cm À1 ) and mono-and di-carbonyls associated with residual sodium cations. The results are interpreted as evidence that site-specified geminal carbonyls are formed with cations possessing an ionic radius bigger than a critical value. This value is different for different positions in various zeolites and is bigger for cations in S II positions in Y zeolites than is the case of cations in a ZSM-5 matrix. Ó

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Section: Coadsorption 12 Co and 13 Co On Mn-zsm-5mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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FTIR study of low-temperature CO adsorption on Mn-ZSM-5 and MnY zeolites. Effect of the zeolite matrix on the formation of Mn2+(CO) geminal species

Hadjiivanov

Ivanova

Kantcheva

et al. 2002

Catalysis Communications

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“…On the other hand, nitric oxide (NO) is the target of paramount importance in environmental catalysis. After Iwamoto's discovery of an unusually high activity of Cu(I) zeolites in NO decomposition and its revival [1][2][3] there has been an ongoing experimental [4][5][6][7][8][9][10][11][12] and theoretical research [13][14][15][16][17][18][19][20][21][22][23] to understand the details of the mechanism of this process. Despite this tremendous effort, there are still a number of unsettled questions, including fundamental query about the nature of the bonding between various forms of copper and NO molecule.…”

Section: Introductionmentioning

confidence: 99%

On the nature of spin- and orbital-resolved Cu+–NO charge transfer in the gas phase and at Cu(I) sites in zeolites

et al. 2012

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Electronic factors essential for NO activation by Cu(I) sites in zeolites are investigated within spin-resolved analysis of electron transfer channels (natural orbitals for chemical valence). NOCV analysis is performed for three DFT-optimized models of Cu(I)-NO site in ZSM-5: [CuNO] ? , (T1)CuNO, and (M7)CuNO. NO as a non-innocent, openshell ligand reveals significant differences between independent deformation density components for a and b spins. Four distinct components are identified: (i) unpaired electron donation from NO p k * antibonding orbital to Cu s,d ; (ii) backdonation from copper d yz to p \ * antibonding orbital; (iii) donation from occupied p k and Cu d xz to bonding region, and (iv) donation from nitrogen lone-pair to Cu s,d . Channel (i), corresponding to one-electron bond, shows-up solely for spin majority and is effective only in the interaction of NO with naked Cu ? . Channel (ii) dominates for models b and c: it strongly activates NO bond by populating antibonding p* orbital and weakens the N-O bond in contrast to channel (i), depopulating the antibonding orbital and strengthening N-O bond. This picture perfectly agrees with IR experiment: interaction with naked Cu ? imposes small blue-shift of NO stretching frequency while it becomes strongly red-shifted for Cu(I) site in ZSM-5 due to enhanced backdonation.

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“…In the earliest NO decomposition schemes, Cu 2+ [25] or Cu 2+ -O − [26] were put forward as catalytic centers without invoking a cyclic redox process. Now, a growing consensus is found that monovalent copper participates in the NO decomposition reaction [27][28][29][30][31][32][33].…”

Section: Introductionmentioning

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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Cu(I)-ZSM-5 zeolites prepared by reaction of H-ZSM-5 with gaseous CuCl: Spectroscopic characterization and reactivity towards carbon monoxide and nitric oxide

Cited by 284 publications

References 21 publications

FTIR study of low-temperature CO adsorption on Mn-ZSM-5 and MnY zeolites. Effect of the zeolite matrix on the formation of Mn2+(CO) geminal species

FTIR study of low-temperature CO adsorption on Mn-ZSM-5 and MnY zeolites. Effect of the zeolite matrix on the formation of Mn2+(CO) geminal species

On the nature of spin- and orbital-resolved Cu+–NO charge transfer in the gas phase and at Cu(I) sites in zeolites

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

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