Recent progress on Al distribution over zeolite frameworks: Linking theories and experiments

Kwak, Seung Jae; Kim, Hyo Seok; Jun, Park Nam; Park, Myung-June; Lee, Won Bo

doi:10.1007/s11814-021-0796-2

Cited by 14 publications

(12 citation statements)

References 52 publications

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“…These results can have wider applicability than zeolite β. Other zeolites such as ferrierite (framework FER) also contain 6MRs with a structure similar to that in zeolite β . T4 sites in FER are analogous to the T5 and T6 sites in *BEA.…”

Section: Resultsmentioning

confidence: 99%

“…Other zeolites such as ferrierite (framework FER) also contain 6MRs with a structure similar to that in zeolite β. 23 T4 sites in FER are analogous to the T5 and T6 sites in *BEA. It has been reported that the double Al-substituted T4−T4 configuration of FER with the Brønsted sites inside the same 6MR is the most stable among other configurations.…”

Section: The Journal Of Physicalmentioning

confidence: 99%

“…There are several experimental methods for studying the acid sites in zeolites�nuclear magnetic resonance ( 27 Al and 29 Si MAS NMR), 21 adsorption of molecules, 22,23 and infrared spectroscopy. Temperature-programmed desorption (TPD) of volatile molecules such as ammonia and pyridine is used for studies of their adsorption energies 24 and the quantity of acid sites.…”

Section: Introductionmentioning

confidence: 99%

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DFT Study on the Stability and the Acid Strength of Brønsted Acid Sites in Zeolite β

Воронцов

Smirniotis

2022

J. Phys. Chem. A

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Acid sites are studied computationally for zeolite β. Different deprotonated and protonated models are used. The issue of difference in the stability of acid sites is addressed. Separate and paired acid sites are created, and their stability and acidity are estimated. The sites in the 6-membered rings have a favorable position; however, the study does not exclude the diversity of sites in other positions. The zeolite module and model chemistry have an influence on the computational results. The influence of the mutual arrangement of two acid sites in a single model is studied. Hydrogen bonding influences the stability and acidity in this case. Four and six acid sites are created that possess hydrogen bonding in the same model. The distance and mutual orientation of the sites affect their stability. Thus, the dipole−dipole interactions, structure deformations, and inductive effect all play their roles in the chemistry of the acid sites. Both thermodynamics and chemical kinetics of the zeolite can influence Al locations in zeolites, and their influence should be concerted according to the linear relation of the free energies.

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Section: Resultsmentioning

confidence: 99%

Section: The Journal Of Physicalmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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DFT Study on the Stability and the Acid Strength of Brønsted Acid Sites in Zeolite β

Воронцов

Smirniotis

2022

J. Phys. Chem. A

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“…ML methods coupled to DFT computations have already emerged for predicting mechanical properties [29], nitrogen adsorption [30], molar volumes, and cohesive energies [31] in zeolites. The success rate of these ML applications to zeolites vary according to the predicted properties and the proposed ML approach [32]. Among the spectroscopy techniques, used to study zeolite structures and chemical compositions, most of the NMR techniques can today be routinely applied to the as-synthesised zeolitic materials.…”

Section: Introductionmentioning

confidence: 99%

Regression Machine Learning Models Used to Predict DFT-Computed NMR Parameters of Zeolites

Gaumard

Dragún²,

Pedroza-Montero

et al. 2022

Computation

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Machine learning approaches can drastically decrease the computational time for the predictions of spectroscopic properties in materials, while preserving the quality of the computational approaches. We studied the performance of kernel-ridge regression (KRR) and gradient boosting regressor (GBR) models trained on the isotropic shielding values, computed with density-functional theory (DFT), in a series of different known zeolites containing out-of-frame metal cations or fluorine anion and organic structure-directing cations. The smooth overlap of atomic position descriptors were computed from the DFT-optimised Cartesian coordinates of each atoms in the zeolite crystal cells. The use of these descriptors as inputs in both machine learning regression methods led to the prediction of the DFT isotropic shielding values with mean errors within 0.6 ppm. The results showed that the GBR model scales better than the KRR model.

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“…[16][17][18][19][20] As a part of this strategy, various approaches have been conceived to improve the performance of zeolite catalysts in various reactions by controlling the distribution of Al in zeolites, which changes the configuration of active sites in the zeolite catalyst. 17,[20][21][22][23][24][25][26] Di Iorio et al proposed a synthetic method for controlling the distribution of Al in chabazite zeolites using mixtures of organic and inorganic structure-directing agents (SDAs). 27 Hoffman et al employed the preceding method to improve the activity of the alkanol dehydration reaction over chabazite zeolite by arranging the framework Al into specific distributions.…”

Section: Introductionmentioning

confidence: 99%

Controlling the distribution of aluminum in a Cu–zeolite catalyst by seed-assisted synthesis to improve its NH₃-SCR activity

Lee

Kim²,

Song

et al. 2022

Catal. Sci. Technol.

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Recent progress on Al distribution over zeolite frameworks: Linking theories and experiments

Cited by 14 publications

References 52 publications

DFT Study on the Stability and the Acid Strength of Brønsted Acid Sites in Zeolite β

DFT Study on the Stability and the Acid Strength of Brønsted Acid Sites in Zeolite β

Regression Machine Learning Models Used to Predict DFT-Computed NMR Parameters of Zeolites

Controlling the distribution of aluminum in a Cu–zeolite catalyst by seed-assisted synthesis to improve its NH₃-SCR activity

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Recent progress on Al distribution over zeolite frameworks: Linking theories and experiments

Cited by 14 publications

References 52 publications

DFT Study on the Stability and the Acid Strength of Brønsted Acid Sites in Zeolite β

DFT Study on the Stability and the Acid Strength of Brønsted Acid Sites in Zeolite β

Regression Machine Learning Models Used to Predict DFT-Computed NMR Parameters of Zeolites

Controlling the distribution of aluminum in a Cu–zeolite catalyst by seed-assisted synthesis to improve its NH3-SCR activity

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Controlling the distribution of aluminum in a Cu–zeolite catalyst by seed-assisted synthesis to improve its NH₃-SCR activity