One-pot pseudomorphic crystallization of mesoporous porous silica to hierarchical porous zeolites

Xing, Jun-Ling; Jiang, Shu-Hua; Pang, Junling; Yuan, En-Hui; Ma, Xiaojian; Lam, Koon-Fung; Xue, Qunji; Zhang, Kun

doi:10.1016/j.matchar.2015.07.015

Cited by 3 publications

(2 citation statements)

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“…One topic omitted from this review based on limited mechanistic studies is the impact of replacing Al with other heteroatoms (e.g., zeotypes such as SAPOs and AlPOs). The addition or substitution of heteroatoms into zeolite growth mixtures has led to disparate effects on synthesis mixtures, which include altering crystallization kinetics, ,, crystal size, ,, phase selection, ,, and other phenomena such as IZT. These effects are in addition to that which is generally of greatest interest and the reason why heteroatoms are typically added to growth mixtures: the ability of heteroatoms to alter acid properties, including density, strength, zoning, or siting. ,− Similar to the effects of Si and Al source selection, the choice of heteroatom reagent has the potential to direct growth pathways from classical to nonclassical (or vice versa) .…”

Section: Zeolite Crystal Growthmentioning

confidence: 99%

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Mallette,

Shilpa,

Rimer

2024

Chem. Rev.

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Zeolite catalysts and adsorbents have been an integral part of many commercial processes and are projected to play a significant role in emerging technologies to address the changing energy and environmental landscapes. The ability to rationally design zeolites with tailored properties relies on a fundamental understanding of crystallization pathways to strategically manipulate processes of nucleation and growth. The complexity of zeolite growth media engenders a diversity of crystallization mechanisms that can manifest at different synthesis stages. In this review, we discuss the current understanding of classical and nonclassical pathways associated with the formation of (alumino)silicate zeolites. We begin with a brief overview of zeolite history and seminal advancements, followed by a comprehensive discussion of different classes of zeolite precursors with respect to their methods of assembly and physicochemical properties. The following two sections provide detailed discussions of nucleation and growth pathways wherein we emphasize general trends and highlight specific observations for select zeolite framework types. We then close with conclusions and future outlook to summarize key hypotheses, current knowledge gaps, and potential opportunities to guide zeolite synthesis toward a more exact science.

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Section: Zeolite Crystal Growthmentioning

confidence: 99%

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Mallette,

Shilpa,

Rimer

2024

Chem. Rev.

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“…[13][14][15][16][17][18] An innovative solution is the direct template synthesis of catalyst systems. [19][20][21][22][23] The use of various structure directing agents at the stage of synthesis of zeolite material followed by removal through ignition makes it possible to achieve a uniform and controlled distribution of pores which is vital for diffusing processes occurring in the catalyst grain.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of hierarchical titanium-containing silicas using different size templates

et al. 2019

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The development of hierarchical catalytic heterogeneous catalytic systems with a controlled micro/mesopore ratio is an important issue in catalysis. The main purpose of the paper is to the establish influence of the size of the template molecule on the main characteristics of hierarchical titanium-containing silicas (H-TS). The H-TS were successfully synthesized by a bi-template method using tetrapropylammonium hydroxide (TPAG) as permanent template of MFI topology and tetramethylammonium bromide (TMAB), tetraethylammonium bromide (TEAB), tetrabutylammonium hydroxide (TBAG), dodecyltrimethylammonium bromide (DTMAB), cetyltrimethylammonium bromide (CTAB), didecyldimethylammonium chloride (DDAC), tetradecylbenzyldimethylammonium bromide (TBDAB) as variable structure-directing agent (SDA) of a different size. The structure and morphology were characterized by X-ray diffraction, a Fourier transform infrared spectroscopy, a Raman spectroscopy, a scanning electron microscopy and low-temperature nitrogen adsorption-desorption. The catalytic properties of the prepared titanium-containing micro-mesoporous silicas for hydroxylation of phenol with H 2 O 2 have been evaluated, and their activities have been compared with those of TS-1 with only micropores. The findings of the research illustrate that with an increase in the molecule volume of the structure-directing agent, there is a decrease in the proportion of the crystalline phase and in the degree of the inclusion of Ti 4+ atoms in the structure of the zeolite material. Increase in the volume of the structure-directing agent leads to the decrease of the crystallinity of the samples and decrease in the specific surface area of the material and in the specific volume of micropores. The result of this research will be used to create a theoretical model of controlled micro-/mesoporous ratio in silicas and it may open new perspectives for their potential application in selective oxidation reactions involving large molecules.

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Preparation, Physicochemical Properties and Functional Characteristics of Micromesoporous Zeolite Materials

Shcherban

Ilyin

2016

Theor Exp Chem

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One-pot pseudomorphic crystallization of mesoporous porous silica to hierarchical porous zeolites

Cited by 3 publications

References 50 publications

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Synthesis and characterization of hierarchical titanium-containing silicas using different size templates

Preparation, Physicochemical Properties and Functional Characteristics of Micromesoporous Zeolite Materials

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