Surface analysis of dealuminated Y zeolites by ESCA

SHYU, J; SKOPINSKI, E; GoodwinJr., J. G.; Sayari, Abdelhamid

doi:10.1016/0169-4332(85)90025-x

Cited by 2 publications

(3 citation statements)

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“…In the case of the γ-Al 2 O 3 -supported sample, the O 1s peak was found to be relatively wide (fwhm of 2.5 eV) with a binding energy of 530.7 eV, which is substantially lower than that in all Y zeolite-supported samples. Consistent with other literature reports, 53,54 this result suggests that the oxygen atoms on the γ-Al 2 O 3 surface are more electron rich as compared to those of the zeolite framework. It is further evident that the Al content in the zeolite framework affects significantly the electronic properties of oxygen atoms associated with Al, as O 1s binding energies increase by approximately 1 eV when the Si/Al ratio increases from 2.6 to 30 (Table 3).…”

Section: Thesupporting

confidence: 92%

Effect of Si/Al Ratio on the Nature and Reactivity of HY Zeolite-Supported Rhodium Dicarbonyl Complexes

et al. 2014

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Fourier transform infrared (FTIR), extended Xray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS) measurements, and DFT calculations were used to characterize the species formed following reaction of a Rh(CO) 2 (acac) precursor with dealuminated HY zeolites with different Si/Al ratios. The results indicate the formation of two types of Rh(CO) 2 species with characteristic ν CO bands at 2117/2053 and 2110/2043 cm −1 . Both species are attached to the zeolite framework and have similar structural properties. However, their thermal stabilities are different, and the fraction of each species formed strongly depends on the Si/Al ratio of the zeolite. The carbonyl ligands in both types of these zeolite-bound Rh(CO) 2 complexes can react with gas-phase C 2 H 4 to form Rh(CO)(C 2 H 4 ) species. However, the reaction rate is substantially higher for the Rh(CO) 2 complex with the ν CO bands at 2117/2053 cm −1 , suggesting that the electronic properties of the Rh site affect the reactivity of the carbonyl ligands. The results further indicate that the two types of Rh(CO) 2 species are not associated with unreacted or partially reacted Rh(CO) 2 (acac) complexes or with the formation of a hydrated Rh(CO) 2 (H 2 O) x -type species. Instead, the results of the DFT calculations suggest that the differences observed can be attributed to differences in the structure of the binding sites in the dealuminated faujasites framework.

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Section: Thesupporting

confidence: 92%

Effect of Si/Al Ratio on the Nature and Reactivity of HY Zeolite-Supported Rhodium Dicarbonyl Complexes

et al. 2014

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“…Increase of the E b values of O 1s and Si 2p photoelectron lines (∼2 eV) and Al 2p photoelectron line (∼1 eV) from zeolite A (Si/Al ∼ 1) to faujasite (Si/Al ∼ 4) was well established. ,,, Much less data are available above this concentration region. The observed decrease of E b of Al 2p, Si 2p, and O 1s photoelectron lines from Si/Al ∼ 4 to Si/Al ∼12 is in agreement with data published in refs and (see Figures −4). This decrease is ∼0.8 eV for Al 2p photoelectron line and ∼0.5 eV for Si 2p and O 1s photoelectron lines.…”

Section: Discussionsupporting

confidence: 93%

“…Data obtained for zeolite A, ferrierite, and ZSM-5 are included to the investigated series of zeolites. Our findings are compared with those known from literature. − The influence of initial and final state effects on the core level E b values is qualitatively discussed. Chemical effects on energy and intensities of Al (Si) KLL Auger line are demonstrated.…”

Section: Introductionmentioning

confidence: 79%

Initial and Final State Effects in the Photoelectron and Auger Spectra of Si and Al Bonded in Zeolites

Jirka

1997

J. Phys. Chem. B

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The dependence of the core level binding energies, E b, of Si, Al, and O bonded in zeolites on the concentration of skeletal Al is investigated. The line shape changes of Al KLL Auger spectra appearing with decreasing concentration of Al in zeolites are described. Initial and final state effects influencing core level binding energies of zeolites are discussed on a qualitative level. Different screening of the hole states localized on Al and Si is demonstrated. Evidence is shown for the dominant influence of initial state effects on the core level E b values of Si and Al.

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Surface analysis of dealuminated Y zeolites by ESCA

Cited by 2 publications

References 0 publications

Effect of Si/Al Ratio on the Nature and Reactivity of HY Zeolite-Supported Rhodium Dicarbonyl Complexes

Effect of Si/Al Ratio on the Nature and Reactivity of HY Zeolite-Supported Rhodium Dicarbonyl Complexes

Initial and Final State Effects in the Photoelectron and Auger Spectra of Si and Al Bonded in Zeolites

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