Cation location and migration in lanthanum-exchanged NaY zeolite

Du, Xiaosheng; Zhang, Haitao; Li, Xueli; Tan, Zhengguo; Liu, Honghai; Gao, Xionghou

doi:10.1016/s1872-2067(11)60622-6

Cited by 36 publications

(33 citation statements)

References 20 publications

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“…Furthermore, when the ion exchange content exceeds 12 La 3+ or 18 E 2+ in one unit cell of Y zeolite, the cell parameters only increase slightly, indicating that the ion content in sodalite cage can almost reach saturation when the ion exchange content reach 12 La 3+ or 18 AE 2+ in one unit cell of Y zeolite, similar results have been reported by Li et al . 27 . In short, the XRD results are in good agreement with the N 2 -physisorption results.…”

Section: Resultsmentioning

confidence: 99%

The effect of positioning cations on acidity and stability of the framework structure of Y zeolite

Deng

Zhang

Dong

et al. 2016

Sci Rep

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The investigation on the modification of NaY zeolite on LaHY and AEHY (AE refers Ca and Sr and the molar ratio of Ca and Sr is 1:1) zeolites was proformed by XRD, N2-physisorption (BET), XRF, XPS, NH3-TPD, Py-IR, hydrothermal stability, and catalytic cracking test. These results indicate that HY zeolite with ultra low content Na can be obtained from NaY zeolite through four exchange four calcination method. The positioning capability of La3+ in sodalite cage is much better than that of AE2+ and about 12 La3+ can be well coordinated in sodalite cages of one unit cell of Y zeolite. Appropriate acid amount and strength favor the formation of propylene and La3+ is more suitable for the catalytic cracking of cyclohexane than that of AE2+. Our results not only elaborate the variation of the strong and weak acid sites as well as the Brönsted and Lewis acid sites with the change of exchanged ion content but also explore the influence of hydrothermal aging of LaHY and AEHY zeolites and find the optimum ion exchange content for the most reserved acid sites. At last, the coordination state and stabilization of ion exchanged Y zeolites were discussed in detail.

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Section: Resultsmentioning

confidence: 99%

The effect of positioning cations on acidity and stability of the framework structure of Y zeolite

Deng

Zhang

Dong

et al. 2016

Sci Rep

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“…573 K for erionite, Y, etc.). 8,22 1073 K, following dehydration at 573 K at to the smaller La 3+ cations in sites I and II, (Table 1). 24 Direct evidence of the La 3+ cations exchanging K + cations in the can cages was obtained by high-resolution STEM of zeolite La3.0-L.…”

Section: Resultsmentioning

confidence: 99%

Hiding extra-framework cations in zeolites L and Y by internal ion exchange and its effect on CO₂ adsorption

et al. 2020

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“…According to Du et al [59], the ratio of the intensities of the reflections of the (311) and (222) planes of the zeolite crystals, K = I (311) /I (222) , is indicative of the rare-earth cations distribution in the supercage and the sodalite cages. A higher value of K points to a larger number of cations located in the sodalite cages, which is the case of the La and Pd/LaY catalysts with a value of K = 1.9.…”

Section: Concentration By Atomic Absorptionmentioning

confidence: 99%

Catalytic Dehydration of Glycerol to Acrolein over a Catalyst of Pd/LaY Zeolite and Comparison with the Chemical Equilibrium

et al. 2017

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Glycerol dehydration to acrolein was studied with three catalysts using zeolite-Y. This zeolite in its protonic form (HY), with La (LaY) and Pd with La (Pd/LaY), was characterized by X-ray diffraction (XRD), Fourier-transform-infrared spectroscopy (FTIR) with pyridine, BET, Scanning Electron Microscope (SEM)-Energy-Dispersive Spectroscopy X-ray (EDS) and the catalytic activity tests were carried out under H 2 atmosphere. It was found that La ions exchanged in the zeolite-Y resulted in the improvement of both glycerol conversion and yield to acrolein, also a relatively constant glycerol conversion was achieved up to three hours, due to the presence of Pd on the catalyst and H 2 in the feed. The comparison of the calculated and experimental yields obtained from the catalytic tests of the Pd/LaY catalyst indicates a greater activity for the reaction to acrolein than for the reaction to acetol. The calculated equilibrium yields of the dehydration reaction from glycerol to acrolein, acetol, ethanal, methanol, and water and the experimental yields of a Pd/LaY catalyst were compared. Thermodynamically, a complete conversion of glycerol can be achieved since the general system remains exothermic and promotes the path to acetol below 480 K. Above this temperature the system consumes energy and favors the production of acrolein, reaching its maximum concentration at 600 K.

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Cation location and migration in lanthanum-exchanged NaY zeolite

Cited by 36 publications

References 20 publications

The effect of positioning cations on acidity and stability of the framework structure of Y zeolite

The effect of positioning cations on acidity and stability of the framework structure of Y zeolite

Hiding extra-framework cations in zeolites L and Y by internal ion exchange and its effect on CO₂ adsorption

Catalytic Dehydration of Glycerol to Acrolein over a Catalyst of Pd/LaY Zeolite and Comparison with the Chemical Equilibrium

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Cation location and migration in lanthanum-exchanged NaY zeolite

Cited by 36 publications

References 20 publications

The effect of positioning cations on acidity and stability of the framework structure of Y zeolite

The effect of positioning cations on acidity and stability of the framework structure of Y zeolite

Hiding extra-framework cations in zeolites L and Y by internal ion exchange and its effect on CO2 adsorption

Catalytic Dehydration of Glycerol to Acrolein over a Catalyst of Pd/LaY Zeolite and Comparison with the Chemical Equilibrium

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Hiding extra-framework cations in zeolites L and Y by internal ion exchange and its effect on CO₂ adsorption