Fluoride- and Seed-Free Synthesis of Pure-Silica Zeolite Adsorbent and Matrix Using OSDA-Mismatch Approach

Ma, Chao; Liu, Xiaona; Hong, Yang; Yan, Nana; Nie, Chenyang; Wang, Jing; Guo, Peng; Liu, Zhongmin

doi:10.1021/jacs.3c08484

Cited by 6 publications

(2 citation statements)

References 46 publications

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“…The design of OSDAs has been instrumental in the development of next-generation zeolites . Many of these designs rely on the multifunctionality of organics to promote the growth of specific crystallographic directions while inhibiting or suppressing others. , Some syntheses (e.g., the charge density mismatch approach) − employ two or more SDAs to cooperatively direct zeolite structures . OSDAs have also been used in combination with exfoliating agents to produce layered materials and new zeolite structures and have been shown to generate enantiomerically enriched chiral zeolite frameworks .…”

Section: Introductionmentioning

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: Introductionmentioning

confidence: 99%

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Mallette,

Shilpa,

Rimer

2024

Chem. Rev.

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“…In order to efficient and low-cost utilization of the zeolites, various strategies have been developed to accelerate their crystallization rates. − These innovative achievements have made great contributions to this topic and extensively promoted the developments and applications of the zeolites. However, there lacks the comprehensive summary and analysis on them.…”

Section: Introductionmentioning

confidence: 99%

Acceleration of Zeolite Crystallization: Current Status, Mechanisms, and Perspectives

Yuan,

Han,

Deng

et al. 2024

ACS Appl. Mater. Interfaces

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Zeolites are important classes of crystalline materials and possess well-defined channels and cages with molecular dimensions. They have been extensively employed as heterogeneous catalysts and gas adsorbents due to their relatively large specific surface areas, high pore volumes, compositional flexibility, definite acidity, and hydrothermal stability. The zeolite synthesis normally undergoes high-temperature hydrothermal treatments with a relatively long crystallization time, which exhibits low synthesis efficiency and high energy consumption. Various strategies, e.g., modulation of the synthesis gel compositions, employment of special silica/aluminum sources, addition of seeds, fluoride, hydroxyl (·OH) free radical initiators, and organic additives, regulation of the crystallization conditions, development of new approaches, etc., have been developed to overcome these obstacles. And, these achievements make prominent contributions to the topic of acceleration of the zeolite crystallization and promote the fundamental understanding of the zeolite formation mechanism. However, there is a lack of the comprehensive summary and analysis on them. Herein, we provide an overview of the recent achievements, highlight the significant progress in the past decades on the developments of novel and remarkable strategies to accelerate the crystallization of zeolites, and basically divide them into three main types, i.e., chemical methods, physical methods, and the derived new approaches. The principles/acceleration mechanisms, effectiveness, versatility, and degree of reality for the corresponding approaches are thoroughly discussed and summarized. Finally, the rational design of the prospective strategies for the fast synthesis of zeolites is commented on and envisioned. The information gathered here is expected to provide solid guidance for developing a more effective route to improve the zeolite crystallization and obtain the functional zeolite-based materials with more shortened durations and lowered cost and further promote their applications.

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Selective and Controllable Cracking of Polyethylene Waste by Beta Zeolites with Different Mesoporosity and Crystallinity

Liu,

Dai,

Zheng

et al. 2024

Advanced Science

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Waste plastics bring about increasingly serious environmental challenges, which can be partly addressed by their interconversion into valuable compounds. It is hypothesized that the porosity and acidity of a zeolite‐based catalyst will affect the selectivity and effectiveness, enabling a controllable and selective conversion of polyethylene (PE) into gas‐diesel or lubricating base oil. A series of embryonic, partial‐ and well‐crystalline zeolites beta with adjustable porosity and acidity are prepared from mesoporous SBA‐15. The catalysts and catalytic systems are studied with nuclear magnetic resonance (NMR), X‐ray diffraction (XRD), and adsorption kinetics and catalytic reactions. The adjustable porosity and acidity of zeolite‐beta‐based catalysts achieve a controllable selectivity toward gas‐diesel or lubricating base oil for PE cracking. With a catalyst with mesopores and appropriate acid sites, a fast escape and reduced production of cracking of intermediates are observed, leading to a significant fraction (88.7%) of lubricating base oil. With more micropores, a high acid density, and strong acid strength, PE is multiply cracked into low carbon number hydrocarbons. The strong acid center of the zeolite is confirmed to facilitate significantly the activation of hydrogen (H2), and, an in situ ammonia poisoning strategy can significantly inhibit hydrogen transfer and effectively regulate the product distribution.

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Fluoride- and Seed-Free Synthesis of Pure-Silica Zeolite Adsorbent and Matrix Using OSDA-Mismatch Approach

Cited by 6 publications

References 46 publications

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Acceleration of Zeolite Crystallization: Current Status, Mechanisms, and Perspectives

Selective and Controllable Cracking of Polyethylene Waste by Beta Zeolites with Different Mesoporosity and Crystallinity

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