Improved hydrothermal stability and acidic properties of ordered mesoporous SBA-15 analogs assembled from nanosized ZSM-5 precursors

Vu, Xuan Hoan; Steinfeldt, Norbert; Armbruster, Udo; Martin, Andreas

doi:10.1016/j.micromeso.2012.05.036

Cited by 18 publications

(17 citation statements)

References 41 publications

(47 reference statements)

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“…Moreover, ascorbic acid is relatively simple to use, non-toxic and environmentally innocuous, in comparison to other reducing agents such as sodium borohydride, hydrazine hydrate or ethylene glycol. With respect to the support, mesoporous silicas, such as SBA-15, possess a weak acidic character [28]. They are, however, characterized by presenting high surface areas and a uniform and tunable porosity, with a narrow pore size distribution [29].…”

Section: Introductionmentioning

confidence: 99%

Enhanced catalytic stability through non-conventional synthesis of Ni/SBA-15 for methane dry reforming at low temperatures

Gálvez

Albarazi

Costa

2015

Applied Catalysis A: General

108

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Section: Introductionmentioning

confidence: 99%

Enhanced catalytic stability through non-conventional synthesis of Ni/SBA-15 for methane dry reforming at low temperatures

Gálvez

Albarazi

Costa

2015

Applied Catalysis A: General

108

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“…Consequently, the hydrothermal stability and acidic properties of the known SBA-15 analogs, e.g., MAS-9 [ 6 ] or MSU-S/H [ 8 ] are still inferior to those of zeolites, being unsatisfactory for industrial applications. Recently, we developed an effective method for further improving the hydrothermal stability and acidic properties of ordered mesoporous SBA-15 analogs assembled from ZSM-5 precursors (denoted as SAZ) by high-temperature synthesis and pH adjustment [ 9 ]. The ordered mesostructure of SAZ materials was well preserved even upon steaming at 1073 K for 4 h with little loss in the specific BET surface area by 11% only, while their acidic properties were substantially enhanced in terms of both number and strength of acid sites.…”

Section: Introductionmentioning

confidence: 99%

High-Temperature Synthesis of Ordered Mesoporous Aluminosilicates from ZSM-5 Nanoseeds with Improved Acidic Properties

Eckelt

Armbruster

et al. 2014

Nanomaterials

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Ordered mesoporous SBA-15 analogs with different Si/Al ratios were successfully prepared in a two-step process from self-assembly of ZSM-5 nanoseeds at high temperature in mildly acidic media (473 K, pH 3.5). The obtained products were characterized as SAXS, XRD, N 2 sorption, FTIR, TEM, NH 3 -TPD, AAS and ICP. The results show that the initial Si/Al molar ratio of ZSM-5 precursors strongly affects the final materials' properties. A highly condensed, well-ordered mesoporous SBA-15 analog with improved hydrothermal stability and acidic properties can be prepared from low aluminum containing ZSM-5 precursors (Si/Al ≥ 20). Reducing the initial Si/Al molar ratio to 10, however, leads to the formation of a disordered mesoporous SBA-15 type material accompanied by degraded textural and acidic properties. The gas phase cracking of cumene, carried out as probe reaction to evaluate Brønsted acidity, reveals that an increased density of Brønsted acid sites has been achieved over the SBA-15 analogs compared to conventional Al-SBA-15 due to the preservation of zeolite building units in the mesopore walls of the SBA-15 analogs.

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“…It was later extended for the synthesis of different mesostructures including hexagonal (MSU-S, MSU-S/H, MAS, SAZ), cubic (MCM-48), wormhole (HMS, MSU-X), and foam-like (MCF, MSU-F) structures from different zeolite seeds such as Y, ZSM-5, Beta etc. under a variety of assembly conditions [13][14][15]. The resulting materials in most cases show ordered mesostructures with retained zeolite building units in the mesopore walls which are thought to be Figure 2.…”

Section: Direct-synthesis Using Zeolite Precursorsmentioning

confidence: 99%

“…With regular mesopores in the range of 2-30 nm, the diffusion regime in OMMs is typically Knudsen diffusion, whose diffusivity is several orders of magnitude higher than that of "configurational" diffusion inside micropores of the zeolite (see Figure 1). Unfortunately, OMMs fail to mimic the key characteristics of zeolites, i.e., high hydrothermal stability and strong intrinsic acidity owing to the non-crystalline nature of mesopore walls, which severely hinder their practical applications [13][14][15]. Hence, it is extremely desirable to design hierarchical zeolitic materials that couple the advantages of both mesoporous materials and microporous crystalline zeolites.…”

Section: Introductionmentioning

confidence: 99%

Micro/Mesoporous Zeolitic Composites: Recent Developments in Synthesis and Catalytic Applications

Armbruster

Martin

2016

Catalysts

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Micro/mesoporous zeolitic composites (MZCs) represent an important class of hierarchical zeolitic materials that have attracted increasing attention in recent years. By introducing an additional mesoporous phase interconnected with the microporosity of zeolites, a hierarchical porous system of MZCs is formed which facilitates molecular transport while preserving the intrinsic catalytic properties of zeolites. Thus, these materials offer novel perspectives for catalytic applications. Over the years, numerous synthesis strategies toward the formation of MZCs have been realized and their catalytic applications have been reported. In this review, the three main synthesis routes, namely direct synthesis using zeolite precursors, recrystallization of zeolites, and zeolitization of preformed mesoporous materials are thoroughly discussed, with focus on prior works and the most recent developments along with prominent examples given from the literature. In addition, the significant improvement in the catalytic properties of MZCs in a wide range of industrially relevant reactions is presented through several representative cases. Some perspectives for the future development of MZCs are also given.

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Improved hydrothermal stability and acidic properties of ordered mesoporous SBA-15 analogs assembled from nanosized ZSM-5 precursors

Cited by 18 publications

References 41 publications

Enhanced catalytic stability through non-conventional synthesis of Ni/SBA-15 for methane dry reforming at low temperatures

Enhanced catalytic stability through non-conventional synthesis of Ni/SBA-15 for methane dry reforming at low temperatures

High-Temperature Synthesis of Ordered Mesoporous Aluminosilicates from ZSM-5 Nanoseeds with Improved Acidic Properties

Micro/Mesoporous Zeolitic Composites: Recent Developments in Synthesis and Catalytic Applications

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