Impact of a polymer modifier on directing the non-classical crystallization pathway of TS-1 zeolite: accelerating nucleation and enriching active sites

Zhang, Jiani; Bai, Risheng; Zhou, Yachuan; Chen, Ziyi; Zhang, Peng; Li, Jiyang; Yu, Jihong

doi:10.1039/d2sc04544c

Cited by 17 publications

(13 citation statements)

References 71 publications

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“…271 These local charge gradients can also increase the ratio of protonated/neutral OSDAs occluded in the crystal structure beyond what would be expected, putatively affecting rates of crystallization. 272 The adsorption of polymers such as polydiallyldimethylammonium (PDDA) 273 or polyacrylamide 274 on zeolite precursors can also induce particle aggregation at an optimal polymer concentration (Figure 13d), enhancing the rate of zeolite crystallization. 275 It was hypothesized that the interstitial regions between aggregated precursor particles provide a confined region that promotes zeolite nucleation through a more rapid exchange of species between solid and solution phases, as illustrated in Figure 13d.…”

Section: Colloidal Particlesmentioning

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: Colloidal Particlesmentioning

confidence: 99%

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Mallette,

Shilpa,

Rimer

2024

Chem. Rev.

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“… 63 Reported crystallization modifiers also include 1,3,5- phenylacetic acid (H 3 BTC), L-lysine, polyacrylamide (PAM), etc. 64 , 65 , 66 The anatase titanium dioxide in the resulting TS-1 sample can also be removed with acid washing. 67 But the pickling process causes a reduction in titanium content.…”

Section: Ts-1 Zeolitementioning

confidence: 99%

Review and perspectives on TS-1 catalyzed propylene epoxidation

Yang,

Liu,

Liu

et al. 2024

iScience

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“…The growth process accorded with the classical crystallization path, that is, the crystal nucleus was formed spontaneously in the liquid phase, and the ions and molecules were assembled to the flat surface, step, and zigzag surface of the crystal interface to obtain a smooth surface. 37 After the addition of the carrier, the surface of TS-1 CA was no longer smooth, and the shape was not spherical. The particles of TS-1 CA were formed by the accumulation of small crystals.…”

Section: Influence Of Crystallization Conditions On Thementioning

confidence: 99%

Monolithic TS-1 Nanocrystals Prepared via Ammonia-Assisted Dry-Gel Conversion for Propylene Epoxidation

Ji,

Cao,

et al. 2024

ACS Appl. Nano Mater.

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Monolithic TS-1 nanocrystals synthesized by dry-gel conversion show the advantage of high yield. In order to explore the crystallization mechanism during the process, experiments were designed to compare in detail the differences between the dry-gel conversion and the hydrothermal method as well as their effects on crystallization. The powder TS-1 nanocrystals obtained through the hydrothermal method exhibited a smooth and nonstacked morphology. Carbon nanotubes on the surface of nickel foam, as the carrier of a monolithic catalyst, provided abundant nucleation sites for the crystallization of TS-1, reducing the volume of crystal nucleation and the required Gibbs free energy. The nanocrystals obtained in the vapor phase were formed by the accumulation of small particles with obvious mesopores. Nanocrystals could not be obtained under anhydrous conditions. Increasing the concentration of ammonia−water in the vapor phase increased the rate of gel dissociation and the concentration of the gel in the liquid phase, thereby enhancing the crystallization rate. The mechanisms by which ammonia promoted titanium entering the framework and reduced the defect sites were proposed by molecular simulation.

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Impact of a polymer modifier on directing the non-classical crystallization pathway of TS-1 zeolite: accelerating nucleation and enriching active sites

Abstract: Crystallization process directly affects the physicochemical properties and active centers of zeolites; however, controllable tuning of the zeolite crystallization process remains a challenge. Herein, we utilized the polymer (polyacrylamide, PAM)...

Cited by 17 publications

References 71 publications

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Review and perspectives on TS-1 catalyzed propylene epoxidation

Monolithic TS-1 Nanocrystals Prepared via Ammonia-Assisted Dry-Gel Conversion for Propylene Epoxidation

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