Cover Picture: Tailored Mesoporosity Development in Zeolite Crystals by Partial Detemplation and Desilication (Adv. Funct. Mater. 1/2009)

Pérez‐Ramírez, Javier; Abelló, Sònia; Bonilla, Adriana; Groen, Johan C.

doi:10.1002/adfm.200890107

Cited by 64 publications

(109 citation statements)

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“…In contrast, when TPA + cations were present in the alkaline solution, V micro remained mostly unaffected, while strongly enhanced V pore (up to 1.10 cm 3 g −1 for USY3-AT2+TPA) and S meso (up to 500 m 2 g −1 for USY3-AT2+TPA) were attained (Figure 11c, Table 3). Undoubtedly, the protective role displayed on MFI [30,50] is also effective for FAU. Therefore, the use of pore-growth moderators during desilication should be particularly efficient for framework comprising large micropores and/or large surface areas.…”

Section: Usymentioning

confidence: 99%

Hierarchical Y and USY Zeolites Designed by Post‐Synthetic Strategies

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Vilé

Pérez‐Ramírez

2011

Adv Funct Materials

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295

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Strategic combinations of affordable and scalable post‐synthetic modifications enabled to design a broad family of hierarchical Y and USY zeolites (FAU topology) independent on the Si/Al ratio. Pristine (Y, Si/Al = 2.4), steamed (USY, Si/Al = 2.6), and steamed and dealuminated (USY, Si/Al = 15 and 30) zeolites were exposed to a variety of acid (H4EDTA and Na2H2EDTA) and base (NaOH) treatments, which led to the introduction of mesopore surfaces up to 500 m2 g−1, while preserving the intrinsic zeolite properties. Pristine Y and USY zeolites (Si/Al ∼ 2.5) required mild dealumination (to Si/Al > 4 in the case of Y) to facilitate subsequent efficient desilication. Alkaline treatment of Y and USY zeolites with low Si/Al ratios (∼4–6) led to an abundance of Al‐rich debris, which could be removed by a subsequent mild acid wash. On the other hand, severely steamed and dealuminated, hence Si‐rich, USY zeolites (Si/Al = 15 and 30) proved extremely sensitive to the alkaline solution, displaying facile dissolution and substantial amorphization. For the latter group of ultra‐stable Y zeolites, the presence of TPA+ in the alkaline solution enables to protect the zeolite structures upon the introduction of mesoporosity by desilication, preserving crystallinity and micropore volume. The sorption and catalytic properties of the hierarchical Y and USY zeolites were superior compared to the conventional counterparts.

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Section: Usymentioning

confidence: 99%

Hierarchical Y and USY Zeolites Designed by Post‐Synthetic Strategies

Verboekend

Vilé

Pérez‐Ramírez

2011

Adv Funct Materials

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295

218

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“…[4,6,36] To study transport characteristics, we performed elution experiments over selected ITQ-4 zeolites using alkanes of different kinetic diameters, i.e., n-butane (0.43 nm) and neopentane (0.62 nm). A similar approach was used by Christensen et al, [37] who reported an increased rate of diffusion in hierarchical porous zeolites prepared by carbon templating.…”

Section: Transportmentioning

confidence: 99%

“…A large number of templating and nontemplating synthesis routes are available to synthesize hierarchical zeolites in the form of nanocrystals, nanosheets, composites, and mesoporous crystals. [4][5][6][7][8][9] Numerous works have proven the positive influence of the introduction of the secondary porosity on the catalytic performance, which is commonly attributed to the shortened diffusion pathlength resulting from the newly introduced mesoporosity. [6] However, aside from the introduced secondary (meso)porosity, it is possible that other changes in the properties of the hierarchical zeolite, e.g., chemical composition, [10] acid site distribution, [11,12] and surface effects, [13,14] are partially responsible for the altered catalytic behavior as well.…”

Section: Introductionmentioning

confidence: 99%

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Interplay of Properties and Functions upon Introduction of Mesoporosity in ITQ‐4 Zeolite

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Groen

Pérez‐Ramírez

2010

Adv Funct Materials

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The introduction of mesoporosity in zeolites is often directly coupled to changes in their overall catalytic performance without the detailed assessment of other key functions required for the rational design of the catalytic process such as accessibility, adsorption, and transport. This study presents an integrated approach to study property–function relationships in hierarchical zeolites. Accordingly, desilication of the 1D ITQ‐4 zeolite in alkaline medium is applied to develop different degrees of mesoporosity. Along with porosity modification, significant changes in composition, structure, and acidity occur. Relationships are established between the physicochemical properties of the zeolites and their characteristics in the adsorption and elution of light hydrocarbons (C2 to C5, alkanes and alkenes) as well as in the catalytic activity in low‐density polyethylene (LDPE) pyrolysis. The recently introduced hierarchy factor can appropriately relate porosity changes to catalytic performance.

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“…And, the new streamlined cover design should do an even better job of showcasing the most eye-catching images from each issue. For example, this issue's cover features a spectacular scanning electron microscopy image by Pé rez-Ramírez et al showing hierarchical zeolite crystals with tailored mesoporosity, [1] while the inside cover displays striking epifluorescence imaging of human cortical bone damage obtained by Ebacher and Wang. [2] We hope that you find this redesign useful; as always, we welcome your comments and suggestions at afm-journal@ wiley-vch.de.…”

mentioning

confidence: 99%