laser-induced luminescence in reduced copper-exchanged Y zeolite

Deson, J.; Lalo, C.; Gédéon, A.; Vasseur, F.; Fraissard, J.

doi:10.1016/0009-2614(96)00667-7

Cited by 16 publications

(7 citation statements)

References 17 publications

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“…From two given values, the τ 1 lifetime is too short (order of magnitude) to be affected by the luminescence decay of Zn 2+ luminescence center and is likely to characterize the electron lifetime at a neighboring higher energetic level (or levels). 1,56 3. RESULTS AND DISCUSSION 3.1.…”

Section: Methodsmentioning

confidence: 99%

“…55 From the two given values, the τ 1 lifetime is too short (order of magnitude) to be affected by the luminescence decay of the Zn 2+ luminescence center and is likely to characterize the electron lifetime at a neighboring higher level (or levels). 1,56 Therefore, the τ 2 value is suggested to characterize the lifetime of the Zn 2+ luminescence center. A shorter luminescence wavelength is associated with a shorter decay time.…”

Section: Methodsmentioning

confidence: 99%

“…This suggests a multilevel model of the luminescence similar to the one suggested for Cu + centers. , Therefore, τ 2 is characterizing Zn 2+ luminescence center. From two given values, the τ 1 lifetime is too short (order of magnitude) to be affected by the luminescence decay of Zn 2+ luminescence center and is likely to characterize the electron lifetime at a neighboring higher energetic level (or levels). , …”

Section: Experimental Sectionmentioning

confidence: 99%

“…Zeolites due to their structure and chemical composition represent essential materials for the chemical industry. Aluminum-rich zeolites are employed for separation and purification of gases, , while silicon-rich ones represent the widest group of the industrial heterogeneous catalyst. − Zeolites are crystalline microporous aluminosilicate frameworks build with corner-sharing [SiO 4 ] 4– tetrahedra partially isomorphously substituted by [AlO 4 ] 5– tetrahedra, which induce the negative charge of the lattice. This negative charge is compensated for by either protons or transition metal cationic species, which can play the role of active sites in acid-catalyzed reactions (protons in Brønsted acid sites SiOHAl) or in redox catalysis (cations of transition metal ions, TMI).…”

Section: Introductionmentioning

confidence: 99%

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Determination of Zn Speciation, Siting, and Distribution in Ferrierite Using Luminescence and FTIR Spectroscopy

et al. 2021

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A methodology for the analysis of the siting of Zn 2+ ions in extra-framework cationic sites of silicon-rich zeolite was developed and demonstrated on Zn-ferrierite samples (Si/Al 8.5, Zn/Al 0.04−0.33). This methodology is based on the FTIR spectroscopy of antisymmetric tetrahedral−octahedral−tetrahedral (T-O-T) vibrations of the zeolite framework perturbed by Zn 2+ ions, combined with a complementary approach based on Zn 2+ luminescence monitored by laser-induced timeresolved luminescence spectroscopy. Three vibration bands in the FTIR spectra of antisymmetric T-O-T vibrations of dehydrated zeolite reflect Zn 2+ ligation in three extra-framework cationic sites of ferrierite zeolite. The band at 935 cm −1 corresponds to Zn 2+ ions in the α-site of ferrierite, the band at 917 cm −1 correspondsto ions in β-site, and the band at 902 cm −1 correspondsto Zn 2+ ions in the γ-site. The extinction coefficient for quantitative analysis of Zn 2+ ions in cationic sites was estimated and exhibited the same value for Zn 2+ cations in all cationic sites, ε = 49.1 ± 3.8 cm•μmol −1 . In all Zn samples, Zn 2+ siting in the β-site prevails, while Zn 2+ ions in the γ-site are of low population or negligible. Time-resolved luminescence showed that bare Zn 2+ ions in the extra-framework cationic sites can be distinguished from Zn 2+ ions in ZnO by a decay time which is several magnitudes longer and a high sensitivity for quenching. The luminescence spectrum of Zn-ferrierites is composed of three bands at 545, 480, and 425 nm attributable to Zn 2+ ions in the α-, β-, and γ-site with luminescence coefficients (for semiquantitative analysis) ζ α = 10.1, ζ β = 9.4, and ζ γ = 8.8 mmol/g of Zn 2+ ions in the α-, β-, and γ-sites, respectively. The analysis of Zn ions in ferrierites showed that ZnH-ferrierites exclusively contain Zn 2+ ions in cationic sites. In the case of the ZnNa-FER sample with maximum Zn loading (Zn/Al 0.33), a small amount of Zn-oxo species can be formed.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Experimental Sectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of Zn Speciation, Siting, and Distribution in Ferrierite Using Luminescence and FTIR Spectroscopy

et al. 2021

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“…Zeolites are crystalline aluminosilicate materials with high importance in the chemical industry, with applications spanning from catalysts in petrochemical processing, biomass conversion, fine chemistry, to the purification of gases. − The common use of zeolites lies in the combination of their unique properties, such as their high mechanical and thermal stability, substantial porosity due to the presence of a regular channel and cavity system, and easy functionalization resulting in the formation of active sites including acid sites (Brønsted and Lewis acidity by introducing protons) or redox sites (by the accommodation of transition metal ions). Introduction of extraframework cationic species is possible due to the charge disbalance caused by the isomorphous substitution of Si atoms with Al ones.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of the Zeolites from SBU: An SSZ-13 Study

et al. 2021

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Zeolite SSZ-13 was successfully synthesized via interzeolite conversion of zeolites X, A, and ZSM-5. Si(4Al) and Si(1Si, 3Al) were monitored by 29 Si MAS NMR spectroscopy and together with the ion exchange capacity to Co(II) ions were employed to monitor secondary building units (SBU) and (SiAl) n sequences transferred from parent X and A zeolites to the structure of SSZ-13. The starting material serves as an Al and partial Si source and has to be disintegrated into linear or branched (SiAl) n sequences. Also, no mutual structural building units, e.g., hexagonal prisms or 6 rings, are required for the formation of SSZ-13 zeolite. Among transferred (SiAl) n sequences, a significant fraction (ca. 45%) is relocated in the form of chains with at least five T atoms containing three Al atoms (Al TRI ), decreasing the ion exchange capacity as only two of the three Al atoms are involved in balancing one Co(II).

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