Chemistry › Inorganic Chemistry

Zeolite Catalysis and Synthesis

Works Count: 66979

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This cluster of papers focuses on the synthesis, characterization, and applications of zeolites in catalysis, with a particular emphasis on mesoporous and hierarchical zeolite materials. It covers topics such as methanol-to-hydrocarbons conversion, shape selectivity, membrane technology, and the use of aluminophosphates in catalytic processes.

Keywords

Zeolites; Catalysis; Mesoporous Materials; Hierarchical Zeolites; Methanol-to-Hydrocarbons; Microporous Crystals; Crystallization Mechanism; Shape Selectivity; Membrane Technology; Aluminophosphates

Delaminated zeolite precursors as selective acidic catalysts

1998-11-01

Avelino Corma , V. Fornés , Sibele B. C. Pergher +2 more

Atlas of Zeolite Framework Types

2007-01-01

Ch. Baerlocher , W.M. Meier , David Olson

Zeolite Molecular Sieves

1984-01-01

Louis D. Rollmann , E.W. Valyocsik , R. D. Shannon

This chapter contains sections titled: Zeolite A Zeolite Y TMA Offretite ZSM-5 This chapter contains sections titled: Zeolite A Zeolite Y TMA Offretite ZSM-5

Hierarchical zeolites: enhanced utilisation of microporous crystals in catalysis by advances in materials design

2008-01-01

Javier Pérez‐Ramírez , Claus H. Christensen , Kresten Egeblad +2 more

The introduction of synthetic zeolites has led to a paradigm shift in catalysis, separations, and adsorption processes, due to their unique properties such as crystallinity, high-surface area, acidity, ion-exchange capacity, … The introduction of synthetic zeolites has led to a paradigm shift in catalysis, separations, and adsorption processes, due to their unique properties such as crystallinity, high-surface area, acidity, ion-exchange capacity, and shape-selective character. However, the sole presence of micropores in these materials often imposes intracrystalline diffusion limitations, rendering low utilisation of the zeolite active volume in catalysed reactions. This critical review examines recent advances in the rapidly evolving area of zeolites with improved accessibility and molecular transport. Strategies to enhance catalyst effectiveness essentially comprise the synthesis of zeolites with wide pores and/or with short diffusion length. Available approaches are reviewed according to the principle, versatility, effectiveness, and degree of reality for practical implementation, establishing a firm link between the properties of the resulting materials and the catalytic function. We particularly dwell on the exciting field of hierarchical zeolites, which couple in a single material the catalytic power of micropores and the facilitated access and improved transport consequence of a complementary mesopore network. The carbon templating and desilication routes as examples of bottom-up and top-down methods, respectively, are reviewed in more detail to illustrate the benefits of hierarchical zeolites. Despite encircling the zeolite field, this review stimulates intuition into the design of related porous solids (116 references).

Understanding chemical reactions between carbons and NaOH and KOH

2002-12-27

M.A. Lillo-Ródenas , Diego Cazorla‐Amorós , Á. Linares-Solano

The Hydrothermal Synthesis of Zeolites: History and Development from the Earliest Days to the Present Time

2003-02-21

Colin S. Cundy , Paul A. Cox

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Hydrothermal Synthesis of Zeolites: History and Development from the Earliest Days to the Present TimeColin S. Cundy and Paul A. CoxView Author Information Centre for Microporous … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Hydrothermal Synthesis of Zeolites: History and Development from the Earliest Days to the Present TimeColin S. Cundy and Paul A. CoxView Author Information Centre for Microporous Materials, Department of Chemistry, UMIST, P.O. Box 88, Manchester M60 1QD, United Kingdom School of Pharmacy and Biomedical Sciences, University of Portsmouth, Saint Michael's Building, White Swan Road, Portsmouth PO1 2DT, United Kingdom Cite this: Chem. Rev. 2003, 103, 3, 663–702Publication Date (Web):February 21, 2003Publication History Received25 June 2002Published online21 February 2003Published inissue 1 March 2003https://pubs.acs.org/doi/10.1021/cr020060ihttps://doi.org/10.1021/cr020060iresearch-articleACS PublicationsCopyright © 2003 American Chemical SocietyRequest reuse permissionsArticle Views28133Altmetric-Citations1762LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Crystallization,Crystals,Genetics,Materials,Zeolites Get e-Alerts

Methanol to Olefins (MTO): From Fundamentals to Commercialization

2015-02-10

Peng Tian , Yingxu Wei , Mao Ye +1 more

The methanol-to-olefins (MTO) reaction is an interesting and important reaction for both fundamental research and industrial application. The Dalian Institute of Chemical Physics (DICP) has developed a MTO technology that … The methanol-to-olefins (MTO) reaction is an interesting and important reaction for both fundamental research and industrial application. The Dalian Institute of Chemical Physics (DICP) has developed a MTO technology that led to the successful construction and operation of the world's first coal to olefin plant in 2010. This historical perspective gives a brief summary on the key issues for the process development, including studies on the reaction mechanism, molecular sieve synthesis and crystallization mechanism, catalyst and its manufacturing scale-up, reactor selection and reactor scale-up, process demonstration, and commercialization. Further challenges on the fundamental research and the directions for future catalyst improvement are also suggested.

Aluminophosphate molecular sieves: a new class of microporous crystalline inorganic solids

1982-02-01

Stephen T. Wilson , Brent M. Lok , Celeste A. Messina +2 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAluminophosphate molecular sieves: a new class of microporous crystalline inorganic solidsStephen T. Wilson, Brent M. Lok, Celeste A. Messina, Thomas R. Cannan, and Edith M. FlanigenCite this: … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAluminophosphate molecular sieves: a new class of microporous crystalline inorganic solidsStephen T. Wilson, Brent M. Lok, Celeste A. Messina, Thomas R. Cannan, and Edith M. FlanigenCite this: J. Am. Chem. Soc. 1982, 104, 4, 1146–1147Publication Date (Print):February 1, 1982Publication History Published online1 May 2002Published inissue 1 February 1982https://pubs.acs.org/doi/10.1021/ja00368a062https://doi.org/10.1021/ja00368a062research-articleACS PublicationsRequest reuse permissionsArticle Views5443Altmetric-Citations1791LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Conversion of methanol to hydrocarbons over zeolite H-ZSM-5: On the origin of the olefinic species

2007-06-06

Morten Bjørgen , Stian Svelle , Finn Joensen +6 more

Zeolites and catalysis

2000-06-01

Jens Weitkamp

Silicoaluminophosphate molecular sieves: another new class of microporous crystalline inorganic solids

1984-10-01

Brent M. Lok , Celeste A. Messina , R. L. Patton +3 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilicoaluminophosphate molecular sieves: another new class of microporous crystalline inorganic solidsBrent M. Lok, Celeste A. Messina, R. Lyle Patton, Richard T. Gajek, Thomas R. Cannan, and Edith … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilicoaluminophosphate molecular sieves: another new class of microporous crystalline inorganic solidsBrent M. Lok, Celeste A. Messina, R. Lyle Patton, Richard T. Gajek, Thomas R. Cannan, and Edith M. FlanigenCite this: J. Am. Chem. Soc. 1984, 106, 20, 6092–6093Publication Date (Print):October 1, 1984Publication History Published online1 May 2002Published inissue 1 October 1984https://pubs.acs.org/doi/10.1021/ja00332a063https://doi.org/10.1021/ja00332a063research-articleACS PublicationsRequest reuse permissionsArticle Views5638Altmetric-Citations858LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Nanozeolites: Synthesis, Crystallization Mechanism, and Applications

2005-04-09

Lubomira Tosheva , Valentin Valtchev

This review focuses on the synthesis, crystallization mechanism, and application of colloidal zeolites. The synthesis formulations and features of different zeolite-type structures prepared in nanosized form are summarized. Special attention … This review focuses on the synthesis, crystallization mechanism, and application of colloidal zeolites. The synthesis formulations and features of different zeolite-type structures prepared in nanosized form are summarized. Special attention is paid to zeolites prepared as stable colloidal suspensions. Next, new insights into zeolite crystallization mechanism gained by using colloidal zeolites as model systems are discussed. Further, the methods for deposition of zeolite nanocrystals from suspensions onto supports of different shapes and compositions used for the fabrication of zeolite films and membranes are reviewed. The use of colloidal zeolites for the fabrication of hierarchical macrostructures is also described. Other uses of nanozeolites for the preparation of functionalized materials, for the synthesis of mesoporous silicas of improved hydrothermal stability, and as seeds for zeolite syntheses are illustrated. The emerging applications of nanozeolites in sensing, optoelectronics, and medicine constitute another topic in this review. Finally, some future trends in the area are envisaged.

Overview of Applications of Biomass Fast Pyrolysis Oil

2004-02-26

Stefan Czernik , A.V. Bridgwater

Fast pyrolysis of biomass is one of the most recent renewable energy processes to have been introduced. It offers the advantages of a liquid product, bio-oil that can be readily … Fast pyrolysis of biomass is one of the most recent renewable energy processes to have been introduced. It offers the advantages of a liquid product, bio-oil that can be readily stored and transported. Bio-oil is a renewable liquid fuel and can also be used for production of chemicals. Fast pyrolysis has now achieved a commercial success for production of chemicals and is being actively developed for producing liquid fuels. Bio-oils have been successfully tested in engines, turbines, and boilers, and have been upgraded to high-quality hydrocarbon fuels, although at a presently unacceptable energetic and financial cost. The paper critically reviews scientific and technical developments in applications of bio-oil to date and concludes with some suggestions for research and strategic developments.

The hydrothermal synthesis of zeolites: Precursors, intermediates and reaction mechanism

2005-04-09

Colin S. Cundy , Paul A. Cox

Impact of Zeolites on the Petroleum and Petrochemical Industry

2009-05-14

Walter Vermeiren , Jean‐Pierre Gilson

Stable single-unit-cell nanosheets of zeolite MFI as active and long-lived catalysts

2009-09-09

Minkee Choi , Kyungsu Na , Jeongnam Kim +3 more

Crystal structure and structure-related properties of ZSM-5

1981-07-01

David H. Olson , G. T. Kokotailo , Stephen L. Lawton +1 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure and structure-related properties of ZSM-5D. H. Olson, G. T. Kokotailo, S. L. Lawton, and W. M. MeierCite this: J. Phys. Chem. 1981, 85, 15, 2238–2243Publication … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure and structure-related properties of ZSM-5D. H. Olson, G. T. Kokotailo, S. L. Lawton, and W. M. MeierCite this: J. Phys. Chem. 1981, 85, 15, 2238–2243Publication Date (Print):July 1, 1981Publication History Published online1 May 2002Published inissue 1 July 1981https://pubs.acs.org/doi/10.1021/j150615a020https://doi.org/10.1021/j150615a020research-articleACS PublicationsRequest reuse permissionsArticle Views8838Altmetric-Citations1043LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Algorithms and tools for high-throughput geometry-based analysis of crystalline porous materials

2011-08-23

Thomas Willems , Chris H. Rycroft , Michaeel Kazi +2 more

Conversion of Methanol to Hydrocarbons: How Zeolite Cavity and Pore Size Controls Product Selectivity

2012-04-18

Unni Olsbye , Stian Svelle , Morten Bjørgen +5 more

Liquid hydrocarbon fuels play an essential part in the global energy chain, owing to their high energy density and easy transportability. Olefins play a similar role in the production of … Liquid hydrocarbon fuels play an essential part in the global energy chain, owing to their high energy density and easy transportability. Olefins play a similar role in the production of consumer goods. In a post-oil society, fuel and olefin production will rely on alternative carbon sources, such as biomass, coal, natural gas, and CO(2). The methanol-to-hydrocarbons (MTH) process is a key step in such routes, and can be tuned into production of gasoline-rich (methanol to gasoline; MTG) or olefin-rich (methanol to olefins; MTO) product mixtures by proper choice of catalyst and reaction conditions. This Review presents several commercial MTH projects that have recently been realized, and also fundamental research into the synthesis of microporous materials for the targeted variation of selectivity and lifetime of the catalysts.

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Phase relationships in the zirconia-yttria system

1975-09-01

H. G. Scott

Inorganic Solid Acids and Their Use in Acid-Catalyzed Hydrocarbon Reactions

1995-05-01

Avelino Corma

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInorganic Solid Acids and Their Use in Acid-Catalyzed Hydrocarbon ReactionsA. CormaCite this: Chem. Rev. 1995, 95, 3, 559–614Publication Date (Print):May 1, 1995Publication History Published online1 May 2002Published … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInorganic Solid Acids and Their Use in Acid-Catalyzed Hydrocarbon ReactionsA. CormaCite this: Chem. Rev. 1995, 95, 3, 559–614Publication Date (Print):May 1, 1995Publication History Published online1 May 2002Published inissue 1 May 1995https://pubs.acs.org/doi/10.1021/cr00035a006https://doi.org/10.1021/cr00035a006research-articleACS PublicationsRequest reuse permissionsArticle Views15526Altmetric-Citations2686LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Methanol-to-hydrocarbons: catalytic materials and their behavior

1999-06-01

Michael Stöcker

Structure of synthetic zeolite ZSM-5

1978-03-01

G. T. Kokotailo , Stephen L. Lawton , David H. Olson +1 more

Optimum Conditions for Adsorptive Storage

2006-01-17

Suresh K. Bhatia , Alan L. Myers

The storage of gases in porous adsorbents, such as activated carbon and carbon nanotubes, is examined here thermodynamically from a systems viewpoint, considering the entire adsorption−desorption cycle. The results provide … The storage of gases in porous adsorbents, such as activated carbon and carbon nanotubes, is examined here thermodynamically from a systems viewpoint, considering the entire adsorption−desorption cycle. The results provide concrete objective criteria to guide the search for the "Holy Grail" adsorbent, for which the adsorptive delivery is maximized. It is shown that, for ambient temperature storage of hydrogen and delivery between 30 and 1.5 bar pressure, for the optimum adsorbent the adsorption enthalpy change is 15.1 kJ/mol. For carbons, for which the average enthalpy change is typically 5.8 kJ/mol, an optimum operating temperature of about 115 K is predicted. For methane, an optimum enthalpy change of 18.8 kJ/mol is found, with the optimum temperature for carbons being 254 K. It is also demonstrated that for maximum delivery of the gas the optimum adsorbent must be homogeneous, and that introduction of heterogeneity, such as by ball milling, irradiation, and other means, can only provide small increases in physisorption-related delivery for hydrogen. For methane, heterogeneity is always detrimental, at any value of average adsorption enthalpy change. These results are confirmed with the help of experimental data from the literature, as well as extensive Monte Carlo simulations conducted here using slit pore models of activated carbons as well as atomistic models of carbon nanotubes. The simulations also demonstrate that carbon nanotubes offer little or no advantage over activated carbons in terms of enhanced delivery, when used as storage media for either hydrogen or methane.

RASPA: molecular simulation software for adsorption and diffusion in flexible nanoporous materials

2015-02-26

David Dubbeldam , Sofı́a Calero , D. E. Ellis +1 more

A new software package, RASPA, for simulating adsorption and diffusion of molecules in flexible nanoporous materials is presented. The code implements the latest state-of-the-art algorithms for molecular dynamics and Monte … A new software package, RASPA, for simulating adsorption and diffusion of molecules in flexible nanoporous materials is presented. The code implements the latest state-of-the-art algorithms for molecular dynamics and Monte Carlo (MC) in various ensembles including symplectic/measure-preserving integrators, Ewald summation, configurational-bias MC, continuous fractional component MC, reactive MC and Baker's minimisation. We show example applications of RASPA in computing coexistence properties, adsorption isotherms for single and multiple components, self- and collective diffusivities, reaction systems and visualisation. The software is released under the GNU General Public License.

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Lanthanum complexes of spheroidal carbon shells

1985-12-01

J. R. Heath , Sean C. O’Brien , Q. Zhang +4 more

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLanthanum complexes of spheroidal carbon shellsJ. R. Heath, S. C. O'Brien, Q. Zhang, Y. Liu, R. F. Curl, F. K. Tittel, and R. E. SmalleyCite this: J. … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLanthanum complexes of spheroidal carbon shellsJ. R. Heath, S. C. O'Brien, Q. Zhang, Y. Liu, R. F. Curl, F. K. Tittel, and R. E. SmalleyCite this: J. Am. Chem. Soc. 1985, 107, 25, 7779–7780Publication Date (Print):December 1, 1985Publication History Published online1 May 2002Published inissue 1 December 1985https://pubs.acs.org/doi/10.1021/ja00311a102https://doi.org/10.1021/ja00311a102research-articleACS PublicationsRequest reuse permissionsArticle Views2263Altmetric-Citations1098LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

The conversion of methanol and other O-compounds to hydrocarbons over zeolite catalysts

1977-05-01

Clarence D. Chang , Anthony J. Silvestri

Geopolymers

1991-08-01

Joseph Davidovits

Spectacular technological progress has been made in the last few years through the development of new materials such as 'geopolymers', and new techniques, such as 'sol-gel'. New state-of-the-art materials designed … Spectacular technological progress has been made in the last few years through the development of new materials such as 'geopolymers', and new techniques, such as 'sol-gel'. New state-of-the-art materials designed with the help of geopolymerization reactions are opening up new applications and procedures and transforming ideas that have been taken for granted in inorganic chemistry. High temperature techniques are no longer necessary to obtain materials which are ceramic-like in their structures and properties. These materials can polycondense just like organic polymers, at temperatures lower than 100‡. Geopolymerization involves the chemical reaction of alumino-silicate oxides (Al3+ in IV-fold coordination) with alkali polysilicates yielding polymeric Si-O-Al bonds; the amorphous to semi-crystalline three dimensional silico-aluminate structures are of the Poly(sialate) type (-SiO-Al-O-), the Poly(sialate-siloxo) type (-Si-O-Al-O-Si-O-), the Poly(sialate-disiloxo) type (-Si-O-Al-O-Si-O-Si-O-). This new generation of materials, whether used pure, with fillers or reinforced, is already finding applications in all fields of industry. Some examples: These applications are to be found in the automobile and aerospace industries, non-ferrous foundries and metallurgy, civil engineering, plastics industries, etc.

Zeolite molecular sieves—Structure, chemistry and use

1975-03-01

H.A. Pearce

Microstructural Optimization of a Zeolite Membrane for Organic Vapor Separation

2003-04-17

Zhiping Lai , Griselda Bonilla , Isabel Dı́az +7 more

A seeded growth method for the fabrication of high-permeance, high-separation-factor zeolite (siliceous ZSM-5, [Si96O192]-MFI) membranes is reported. The method consists of growing the crystals of an oriented seed layer to … A seeded growth method for the fabrication of high-permeance, high-separation-factor zeolite (siliceous ZSM-5, [Si96O192]-MFI) membranes is reported. The method consists of growing the crystals of an oriented seed layer to a well-intergrown film by avoiding events that lead to a loss of preferred orientation, such as twin overgrowths and random nucleation. Organic polycations are used as zeolite crystal shape modifiers to enhance relative growth rates along the desirable out-of-plane direction. The polycrystalline films are thin (approximately 1 micrometer) with single grains extending along the film thickness and with large in-plane grain size (approximately 1 micrometer). The preferred orientation is such that straight channels with an open diameter of approximately 5.5 angstroms run down the membrane thickness. Comparison with previously reported membranes shows that these microstructurally optimized films have superior performance for the separation of organic mixtures with components that have small differences in size and shape, such as xylene isomers.

GULP: A computer program for the symmetry-adapted simulation of solids

1997-01-01

Julian D. Gale

J. D. Gale, J. Chem. Soc., Faraday Trans., 1997, 93, 629 DOI: 10.1039/A606455H J. D. Gale, J. Chem. Soc., Faraday Trans., 1997, 93, 629 DOI: 10.1039/A606455H

State of the art and future challenges of zeolites as catalysts

2003-05-01

Avelino Corma

Hybrid Inorganic-Organic Mesoporous Silicates—Nanoscopic Reactors Coming of Age

2000-10-01

A. Stein , B. J. Melde , Rick C. Schroden

This review describes methods of preparing hybrid inorganic–organic mesoporous silicates with uniform channel structures, as well as some of their applications. Both reactive and passive organic groups can be incorporated … This review describes methods of preparing hybrid inorganic–organic mesoporous silicates with uniform channel structures, as well as some of their applications. Both reactive and passive organic groups can be incorporated in the porous solids by grafting methods or by co-condensation under surfactant control. Functional groups have been placed selectively on the internal or external pore surfaces or even within the walls of the mesoporous solids. Organic functionalization of these solids permits tuning of the surface properties (hydrophilicity, hydrophobicity, binding to guest molecules), alteration of the surface reactivity, protection of the surface from attack, and modification of the bulk properties (e.g., mechanical or optical properties) of the material. Recent applications of hybrid mesoporous silicates are highlighted, including catalysis, sorption of metals, anions, and organics, reactors for polymerization, fixation of biologically active species, and optical applications.

The Mechanism of Methanol to Hydrocarbon Catalysis

2003-03-27

James F. Haw , Weiguo Song , David M. Marcus +1 more

The process of converting methanol to hydrocarbons on the aluminosilicate zeolite HZSM-5 was originally developed as a route from natural gas to synthetic gasoline. Using other microporous catalysts that are … The process of converting methanol to hydrocarbons on the aluminosilicate zeolite HZSM-5 was originally developed as a route from natural gas to synthetic gasoline. Using other microporous catalysts that are selective for light olefins, methanol-to-olefin (MTO) catalysis may soon become central to the conversion of natural gas to polyolefins. The mechanism of methanol conversion proved to be an intellectually challenging problem; 25 years of fundamental study produced at least 20 distinct mechanisms, but most did not account for either the primary products or a kinetic induction period. Recent experimental and theoretical work has firmly established that methanol and dimethyl ether react on cyclic organic species contained in the cages or channels of the inorganic host. These organic reaction centers act as scaffolds for the assembly of light olefins so as to avoid the high high-energy intermediates required by all "direct" mechanisms. The rate of formation of the initial reaction centers, and hence the duration of the kinetic induction period, can be governed by impurity species. Secondary reactions of primary olefin products strongly reflect the topology and acid strength of the microporous catalyst. Reaction centers form continuously through some secondary pathways, and they age into polycyclic aromatic hydrocarbons, eventually deactivating the catalyst. It proves useful to consider each cage (or channel) with its included organic and inorganic species as a supramolecule that can react to form various species. This view allows us to identify structure−activity and structure selectivity relationships and to modify the catalyst with degrees of freedom that are more reminiscent of homogeneous catalysis than heterogeneous catalysis.

Determination of Integrated Molar Extinction Coefficients for Infrared Absorption Bands of Pyridine Adsorbed on Solid Acid Catalysts

1993-06-01

C.A. Emeis

Introduction to Zeolite Science and Practice

1991-01-01

H. van Bekkum

Amphiphilic organosilane-directed synthesis of crystalline zeolite with tunable mesoporosity

2006-08-06

Minkee Choi , Hae Sung Cho , Ruchi Srivastava +3 more

Pore size distribution analysis of microporous carbons: a density functional theory approach

1993-05-01

Christian M. Lastoskie , Keith E. Gubbins , N. Quirke

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPore size distribution analysis of microporous carbons: a density functional theory approachChristian Lastoskie, Keith E. Gubbins, and Nicholas QuirkeCite this: J. Phys. Chem. 1993, 97, 18, 4786–4796Publication … ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPore size distribution analysis of microporous carbons: a density functional theory approachChristian Lastoskie, Keith E. Gubbins, and Nicholas QuirkeCite this: J. Phys. Chem. 1993, 97, 18, 4786–4796Publication Date (Print):May 1, 1993Publication History Published online1 May 2002Published inissue 1 May 1993https://pubs.acs.org/doi/10.1021/j100120a035https://doi.org/10.1021/j100120a035research-articleACS PublicationsRequest reuse permissionsArticle Views7187Altmetric-Citations1028LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

Recent advances in the textural characterization of hierarchically structured nanoporous materials

2016-10-19

Katie A. Cychosz , Rémy Guillet‐Nicolas , Javier García‐Martínez +1 more

This review focuses on important aspects of applying physisorption for the pore structural characterization of hierarchical materials such as mesoporous zeolites. During the last decades major advances in understanding the … This review focuses on important aspects of applying physisorption for the pore structural characterization of hierarchical materials such as mesoporous zeolites. During the last decades major advances in understanding the adsorption and phase behavior of fluids confined in ordered nanoporous materials have been made, which led to major progress in the physisorption characterization methodology (summarized in the 2015 IUPAC report on physisorption characterization). Here we discuss progress and challenges for the physisorption characterization of nanoporous solids exhibiting various levels of porosity from micro- to macropores. While physisorption allows one to assess micro- and mesopores, a widely employed method for textural analysis of macroporous materials is mercury porosimetry and we also review important insights associated with the underlying mechanisms governing mercury intrusion/extrusion experiments. Hence, although the main focus of this review is on physical adsorption, we strongly emphasize the importance of combining advanced physical adsorption with other complementary experimental techniques for obtaining a reliable and comprehensive understanding of the texture of hierarchically structured materials.

Diffusion in Zeolites and Other Microporous Solids.

1993-01-01

R. Mann

The physics of block copolymers

1999-11-01

Ian W. Hamley

1. Introduction 2. Melt Phase Behaviour of Block Copolymers 3. Block Copolymers in Dilute Solution 4. Block Copolymers in Semidilute and Concentrated Solutions 5. Solid State Structure of Block Copolymers … 1. Introduction 2. Melt Phase Behaviour of Block Copolymers 3. Block Copolymers in Dilute Solution 4. Block Copolymers in Semidilute and Concentrated Solutions 5. Solid State Structure of Block Copolymers 6. Blends Containing Block Copolymers Appendix: The Self Consistent Field Theory

Handbook of Zeolite Science and Technology

2003-07-31

Scott M. Auerbach , Kathleen A. Carrado , Prabir K. Dutta

Zeolite chemistry and catalysis

1991-05-01

Jule A. Rabó

Crude‐to‐Chemical Revolution: Integrating Technologies, Economic Feasibility, and Policy Frameworks for Sustainable Light Olefin Production

2025-06-25

Aliyu Musa Alhassan , Basiru O. Yusuf , Ijaz Hussain +4 more | The Chemical Record

Light olefins such as propylene and ethylene are vital building blocks for producing plastics, fibers, resins, and numerous other chemical products. The global demand for basic chemicals is estimated at … Light olefins such as propylene and ethylene are vital building blocks for producing plastics, fibers, resins, and numerous other chemical products. The global demand for basic chemicals is estimated at 700 million tons annually and is projected to reach one billion tons by 2050. Converting crude oil directly to light olefins offers significant advantages, including reduced energy consumption, faster processing times, and the ability to meet growing market demands. This review provides a comprehensive analysis of crude‐to‐chemical (C2C) conversion technology, with a focus on economic sustainability, environmental impact, and policy implications. Key aspects include catalyst engineering, reaction mechanisms, and strategies to enhance light olefin selectivity. The review delves into the catalytic cracking reaction mechanisms, catalyst design and optimization, the roles of surface acidity and mesoporosity, and the effects of metal incorporation on selectivity. Additionally, a technoeconomic feasibility analysis is provided, highlighting the current challenges and future outlook for advancing C2C conversion technologies.

Controllable Encapsulation of Highly Dispersed Pt Clusters in Beta Zeolites

2025-06-25

Xin Jiang , Ye Yang , Zhiguang Zhou +4 more | Catalysis Letters

Synthesis of nanocrystalline aggregate ZSM-5 zeolite with novel organosiloxane and the catalytic for C8 aromatics isomerization

2025-06-24

Yunlong Ding , Jia‐Yin Wang , Yanting Zhang +6 more | Journal of Porous Materials

Hydroxyl Free-Radical-Assisted Synthesis of the ZSM-58 Zeolite Membrane for CO2/CO Separation

2025-06-24

Yifei Wang , Yingdong Yang , Yuxing Liu +7 more | Industrial & Engineering Chemistry Research

Enhanced Hydrothermal Stability and Propylene Selectivity of Electron Beam Irradiation-Induced Hierarchical Fluid Catalytic Cracking Additives

2025-06-24

Nguyen Xuan Phuong Vo , Thuy Phuong Ngo , Van Tri Tran +3 more | Catalysts

A cheap, environmentally friendly, easily scalable post-treatment of Na-ZSM-5 (Si/Al molar ratio = 20 or 30) via electron-beam irradiation to produce hierarchical H-ZSM-5 as a propylene-increasing fluid catalytic cracking additive … A cheap, environmentally friendly, easily scalable post-treatment of Na-ZSM-5 (Si/Al molar ratio = 20 or 30) via electron-beam irradiation to produce hierarchical H-ZSM-5 as a propylene-increasing fluid catalytic cracking additive was performed. Higher specific surface areas and highly accessible porous systems were obtained among the irradiated samples. A combination of 27Al, 1H magic angle spinning nuclear magnetic resonance and NH3-temperature-programmed desorption methods showed that upon irradiation, some of the framework’s tetrahedral Al atoms were removed as non-framework Al atoms via flexible coordination with Si-OH groups (either framework or non-framework defects), thus increasing the H-ZSM-5 acidity and stability during hydrothermal dealumination. The enhanced selectivity and stability toward propylene production over the irradiated H-ZSM-5 samples were attributed to the integration of the reserved population of medium acid sites into the highly accessible hierarchical network. N2 adsorption–desorption isotherm data showed that the Si-rich H-ZSM-5 samples possessed an obvious ink-bottle-shaped micro-mesopore network and a greater degree of disordered orientation of the straight pore systems toward the exterior surfaces. Micro-activity test data suggested that with an increasing Si/Al ratio, the H-ZSM-5 additives lost some extent of their cracking activity due to the constricted hierarchical pore network toward the exterior surface but gained more stability and selectivity for propylene due to the reserved medium acid sites.

Facile Synthesis of Na2Ti6O13 Nanorods by Ultrasonic Spray Pyrolysis Combined with Molten Salt Method and Their Radionuclide and Heavy Metal Sorption Capacity

2025-06-24

Ha Jin Kim , Hee Yeon Jeon , J.H. Kim +2 more | MATERIALS TRANSACTIONS

Mechanisms of metal active site diffusion and function in 3D cavity-structured ZSM-5 evolution (solid → yolk-shell → hollow) during coal-derived oil conversion to light aromatics

2025-06-24

Wei Wang , Qiuxiang Yao , Ming Sun +4 more | Fuel

Increasing para-Xylene Selectivity during Polyolefins to Aromatics via an Olefin Intermediate Tandem Catalysis Process

2025-06-20

Xinyu Zhang , Anping Tao , Zhaohui Chen +6 more | ACS Sustainable Chemistry & Engineering

Prospect of Modification Treatment and Application of Natural Zeolite Materials

2025-06-20

Yan Li , Nan Lu | Scientific Journal of Technology

The efficient and extensive utilization of natural zeolites is restricted by factors such as pore blockage, weak ion exchange selectivity, and small adsorption capacity. Modifying natural zeolite materials is an … The efficient and extensive utilization of natural zeolites is restricted by factors such as pore blockage, weak ion exchange selectivity, and small adsorption capacity. Modifying natural zeolite materials is an important means to enhance their performance and value. Based on existing research results, this paper summarizes the characteristics of inorganic treatment, thermal modification, organic modification, metal loading and composite modification of zeolite materials, as well as their main applicable conditions and influencing factors. Finally, it looks forward to the challenges of large-scale production and application of modified natural zeolites, and proposes to strengthen research and practice in green and efficient modification processes, new functional targeted modification, intelligent manufacturing and application monitoring, etc., to provide scientific references for the high-value utilization of natural zeolite resources.

Enhanced F-Gases’ Recovery by Introducing Lewis Acid Sites into MFI Zeolites

2025-06-20

Ying Zhang , Yue Wu , Tong Yan +3 more | Industrial & Engineering Chemistry Research

Correlating Structural Variation with Catalytic Performance of Hierarchical Zeolites Using Ultra‐High‐Field Solid‐State NMR

2025-06-20

Zhipeng Qie , Joseph Hurd , Noemi Linares +7 more | ChemCatChem

Abstract Ultra‐high‐field solid‐state NMR spectroscopy (1.0 GHz, 23.5 T) was employed to reveal the structural evolution of aluminum species and thus their correlations to catalytic cracking performance of Y zeolites … Abstract Ultra‐high‐field solid‐state NMR spectroscopy (1.0 GHz, 23.5 T) was employed to reveal the structural evolution of aluminum species and thus their correlations to catalytic cracking performance of Y zeolites after post‐synthetic treatments. Microwave‐assisted treatments, including chelating dealumination and NH 4 OH treatment, induced significant changes in both framework and extra‐framework aluminum species. NMR analysis identified that the interaction between extra‐framework Al(V/VI) and Brønsted acid sites (BAS) play a crucial role in enhancing catalytic efficiency. The hierarchical zeolite Y‐MWNH3‐0.1–30 exhibited superior catalytic cracking performance, achieving high yields of light hydrocarbons (C 1 –C 4 ), and excellent selectivity toward BTX during the cracking of bulky molecules. These findings provide new insights into how post‐synthetic modifications can be used to tune aluminum species distribution and acid site interaction, optimizing zeolite catalysts for hydrocarbon conversion performance.

Regulating the Morphology and Catalytic Performance of Titanium Silicalite-2 Zeolite

2025-06-19

Xin Wang , Yi Zuo , Gudan Li +4 more | Industrial & Engineering Chemistry Research

Design and Synthesis of Core-Shell Y Zeolite: A Tandem Microreactor Facilitating Efficient and Targeted Conversion of Heavy Oil Macromolecules

2025-06-19

Bo Qin , Tao Zhang , Yanchao Liu +5 more | Materials Today Sustainability

Rapid Fabrication of ZSM-5/AlPO4-5 Composites via Microwave-Ionothermal Strategy for Enhanced Methanol-to-Olefins Catalysis

2025-06-19

Han Li , Mengting Zhang , Hao Li +7 more | Catalysts

Microwave-assisted ionothermal strategies offer an effective pathway for rapid zeolite crystallization under mild conditions, while conventional ionothermal approaches are still constrained by prolonged crystallization cycles that limit their industrial applicability. … Microwave-assisted ionothermal strategies offer an effective pathway for rapid zeolite crystallization under mild conditions, while conventional ionothermal approaches are still constrained by prolonged crystallization cycles that limit their industrial applicability. Herein, we report a microwave-activated, ionic liquid-mediated synthesis strategy that enables the precise modulation of crystallization kinetics and composite assembly. By introducing ZSM-5 seeds into the ionic liquid system, the nucleation and growth of AlPO4-5 were significantly accelerated, reducing crystallization time by up to 75% (optimal condition: 60 min). Among various imidazolium-based ionic liquids, [BMMIm]Br demonstrated an optimal balance of hydrophilic and hydrophobic interactions, yielding composite zeolites with high surface area (350 m2·g−1) and large pore volume (0.28 cm3·g−1). Comprehensive characterization (XRD, SEM-EDX, NH3-TPD) confirmed the formation of well-defined ZSM-5/AlPO4-5 core–shell structures and revealed tunable acid site distributions depending on the ionic liquid used. In methanol to olefins (MTO) reactions, the composite catalyst exhibited outstanding selectivity towards light olefins (C2=–C4=: 72.84%), markedly outperforming the individual ZSM-5 and AlPO4-5 components. The superior catalytic behavior is primarily attributed to the synergistic effect of hierarchical acid site tuning and the integrated core–shell architecture, which together optimize reaction selectivity. This strategy provides a promising route for the rational design of high-performance zeolites with significant industrial applicability.

Desing of Homometallic Nanosites-Confined Hierarchical and Bulk Zeolites for Tandem Catalysis

2025-06-18

Volkan Şahin , Neslisah Cihan , Büşra Dila Çar | ACS Applied Nano Materials

ZSM-5 zeolite for catalytic pyrolysis of light hydrocarbons to increase light olefins: Research on the loss and stability of Al

2025-06-18

Meijia Liu , Zhongdong Zhang , Shuai Qian +3 more | Journal of Analytical and Applied Pyrolysis

High-Pressure Selective Topotactic Synthesis of Ordered Trans-Polymeric CS2 in a Zeolite

2025-06-17

Mario Santoro , Sebastiano Romi , Frederico Alabarse +2 more | Inorganic Chemistry

High-pressure polymerization of CS2 leads to structurally and stoichiometrically disordered solids, making characterization of the products and of reaction mechanisms challenging. This is due to the multiplicity of chemical pathways … High-pressure polymerization of CS2 leads to structurally and stoichiometrically disordered solids, making characterization of the products and of reaction mechanisms challenging. This is due to the multiplicity of chemical pathways that CS2 is subject to in the free space. We reduced this multiplicity by constraining polymerization in a confined space. We inserted liquid CS2 in the one-dimensional pores of the all-siliceous zeolite Theta-One, subjected the mixture to maximum temperatures and pressures of 250 °C and 14 GPa, and recovered a darkened sample at ambient conditions. Synchrotron X-ray diffraction was performed on the materials. Full structural refinements, using ab initio calculated structures as starting models, show that CS2 in the zeolite undergoes selective topotactic polymerization, resulting in the ordered trans-isomer of the long-sought-after Bridgman's black polymer (-(C═S)-S-)n. We provide physical insight into the reaction mechanism by proposing that it consists of a molecular bending followed by addition. The trans-polymer forms spontaneously from the unstable, confined monomer upon relaxation in ab initio calculations.

How Do Zn2+ Ions Promote Methane Activation on Zinc-Modified Zeolites? A Hybrid Quantum-Chemical Study

2025-06-17

Zoya N. Lashchinskaya , Anton A. Gabrienko , Alexander G. Stepanov | Inorganic Chemistry

It was earlier established that Zn2+ species loaded in zeolites promoted alkane C-H bond activation by Brønsted acid sites (BAS). It was found that the rate of H/D hydrogen exchange … It was earlier established that Zn2+ species loaded in zeolites promoted alkane C-H bond activation by Brønsted acid sites (BAS). It was found that the rate of H/D hydrogen exchange between alkane and zeolite BAS increased dramatically, and the activation barrier decreased for Zn2+-modified zeolite compared to H-form zeolite. However, it still remains unclear what the nature of the promoting effect of Zn2+ species on C-H bond activation is. In this work, the possible mechanisms of methane hydrogen exchange on the Zn2+/H-ZSM-5 zeolite have been analyzed by means of hybrid quantum chemical calculations (PBEh-3c/DLPNO-CCSD(T)). Four models representing various locations of Zn2+ ions in H-ZSM-5 differing in Al distribution and local geometry have been investigated. Zn2+ sites are found to be rather diverse in their adsorption properties and reactivity. The earlier accepted hypothesis of H/D hydrogen exchange promotion via the formation of a transient molecular complex of methane with Zn2+ sites has been disproven by the PBEh-3c/DLPNO-CCSD(T) calculations. Conversely, the two-step mechanism of hydrogen exchange in methane on Zn2+/H-ZSM-5 involving zinc-methyl species formation is concluded to be the most probable. Thus, the rationalization of how Zn2+ sites affect alkane C-H bond activation by BAS has been provided.

Synthesis of activated carbon from phenolic resin by physicochemical activation with copper and CO2

2025-06-17

Sávia Del Vale Terra Nadaleti , Pricila Maria Batista Chagas , Mário César Guerreiro | Materials Science and Engineering B

Powders Synthesized from Water Solutions of Sodium Silicate and Calcium and/or Magnesium Chlorides

2025-06-16

Т. В. Сафронова , Alexandra S. Sultanovskaya , С. В. Савельев +7 more | Compounds

Powders with phase composition including quasi-amorphous phases and calcium carbonate CaCO3 in the form of calcite or aragonite and sodium halite NaCl as a reaction by-product were synthesized from 0.5M … Powders with phase composition including quasi-amorphous phases and calcium carbonate CaCO3 in the form of calcite or aragonite and sodium halite NaCl as a reaction by-product were synthesized from 0.5M aqua solutions of sodium silicate and 0.5M aqua solutions of calcium and/or magnesium chlorides. Starting solutions were taken in quantities which could provide precipitation of hydrated calcium and/or magnesium silicates with molar ratios Ca/Si = 1 (CaSi), Mg/Si = 1 (MgSi) or (Ca+Mg)/Si = 1 (CaMgSi). Hydrated calcium and/or magnesium silicates, hydrated silica, magnesium carbonate, hydrated magnesium carbonate or hydrated magnesium silicate containing carbonate ions are suspected as components of quasi-amorphous phases presented in synthesized powders. Heat treatment of synthesized powders at 400, 600, 800 °C and pressed preceramic samples at 900, 1000, 1100 and 1200 °C were used for investigation of thermal evolution of the phase composition and microstructure of powders and ceramic samples. Mass loss of powder samples under investigation during heat treatment was provided due to evacuation of H2O (m/z = 18), CO2 (m/z = 44) and NaCl at temperatures above its melting point. After sintering at 1100 °C, the phase composition of ceramic samples included wollastonite CaSiO3 (CaSi_1100); enstatite MgSiO3, clinoenstatite MgSiO3 and forsterite Mg2SiO4 (MgSi_1100); and diopside CaMgSi2O6 (CaMgSi_1100). After sintering at 1200 °C, the phase composition of ceramics CaSi_1200 included pseudo-wollastonite CaSiO3. After heat treatment at 1300 °C, the phase composition of MgSi_1300 powder included preferably protoenstatite MgSiO3. The phase composition of all samples after heat treatment belongs to the oxide system CaO–MgO–SiO2. Ceramic materials in this system are of interest for use in different areas, including refractories, construction materials and biomaterials. Powders prepared in the present investigation, both via precipitation and via heat treatment, can be used for the creation of materials with specific properties and in model experiments as lunar regolith simulants.

Minimizing Sinusoidal Channels of ZSM‐5 for Propene Production From Molecular Traffic Controlled Cracking Reaction

2025-06-16

Shiqing Li , Jie Tuo , Wan Zheng +7 more | Small

Abstract The molecular traffic control (MTC) effect, a critical concept in porous materials catalysis, describes the diffusion behavior of reactant and product molecules through pore channels within zeolites, thereby establishing … Abstract The molecular traffic control (MTC) effect, a critical concept in porous materials catalysis, describes the diffusion behavior of reactant and product molecules through pore channels within zeolites, thereby establishing a relationship between the pore system and the catalytic performance. Herein, a series of a ‐oriented MFI ‐type ZSM‐5 catalysts with modulated orientation length while maintaining comparable physicochemical properties are synthesized, and their performance in butene cracking reactions are evaluated. By precisely modulating the pore structure and crystal morphology of ZSM‐5, it is demonstrated that minimizing the sinusoidal channel length along a ‐axis effectively optimizes the MTC effect, resulting in a superior propene selectivity (≈60%) and an enhanced propene‐to‐ethene ratio (≈12). Computational simulations coupled with experimental measurements reveal that reducing the length along a ‐axis facilitates preferential outward diffusion of propene molecules as terminal products. This work not only provides solid proof of molecular traffic control but also offers theoretical guidance for the rational design of other useful porous catalysts.

Effects of crystallization time and composition of gel for preparing of zeolite K-F

2025-06-15

Xueshi Zhang , Yuhua Sun , Qunqing Li +3 more | Digest Journal of Nanomaterials and Biostructures

Zeolite K-F crystals were prepared by a hydrothermal route, the effects of crystallization time as well as composition of gel (K2O/SiO2 and Al2O3/SiO2) on the final samples were studied. The … Zeolite K-F crystals were prepared by a hydrothermal route, the effects of crystallization time as well as composition of gel (K2O/SiO2 and Al2O3/SiO2) on the final samples were studied. The results displayed that when heating time was increased to 24 h, cubic aggregates with well-developed faces were observed. In detail, the parent zeolite aggregates with size variation (2-5 um) were composed of flattened cuboid shaped primary crystals. Higher K2O/SiO2 ratio was favorable for the generation of smaller individual primary zeolite K-F nanosized crystals, resulting in forming large steady congregated agglomerates. However, too strong alkalinity resulted in amorphous materials produced. Moreover, batch molar ratio Al2O3/SiO2 determined whether or not zeolite K-F was formed. The product obtained at Al2O3/SiO2=0.15 was a single phase of zeolite W; Well-crystallized zeolite K-F samples were obtained at Al2O3/SiO2 ratios of 0.65, 0.92, 1.45, 2.03 and 2.34. With the Al2O3/SiO2 was increased to 3.05, needle-type hexagonal cancrinite crystals were generated.

Green catalytic oxidation of 4-ethyltoluene to 4-methylacetophenone over modified flake micro-mesoporous TS-1 zeolite supported cobalt catalysts

2025-06-15

Zhimei Song , Chang Cai , Yu Wang +7 more | Chemical Physics Letters

A comparative study on the physicochemical and hydrogen adsorption properties of Ag-exchanged Demirci (Türkiye) clinoptilolites

2025-06-14

Burcu Erdoğan Alver , Bala Ekinci Şans , Fahri Esenli | International Journal of Hydrogen Energy

In-situ carbonate mineral coupling by hydrothermal carbonization: a strategy for enhanced hydrochar stability and long-term carbon sequestration

2025-06-13

Xin Luo , Xiangjun Pei , Xiaochao Zhang +3 more | Fuel

Defect-Engineered Silicalite-1 Monoliths for Enhanced Hydrophobicity in Room-Temperature Tritium Oxidation

2025-06-12

Benlong Yu , Tao Wang , Chao Xiao | Catalysts

This study describes a monolithic silicalite-1 catalyst support designed for tritium oxidation reactions under humid conditions. Monolithic molecular sieves (sil-s) were fabricated by converting silica binders to silicalite-1 through secondary … This study describes a monolithic silicalite-1 catalyst support designed for tritium oxidation reactions under humid conditions. Monolithic molecular sieves (sil-s) were fabricated by converting silica binders to silicalite-1 through secondary crystallization (175 °C, 24 h). In addition to the binder conversion to silicalite-1, some recrystallization of starting silicalite-1 (sil) results in higher crystallinity, lower concentration of silanol defects, and higher hydrophobicity. With the addition of 2% platinum, Pt/sil-s exhibited better stability under humid conditions, showing only 0.01%/min conversion decay over 800 min. This work has demonstrated a moisture-resistant Pt catalyst for tritium oxidation in fusion energy systems.

Zeolite beta nanosponge with high acidity on mesopores for efficient tributyrin transesterification

2025-06-12

Jeong‐Chul Kim , Kyungmin Cho , Shin Hyuk Kim +4 more | Fuel

Hierarchical Nanosized ZSM-5 for Enhanced Selectivity of Para-Xylene in the Alkylation of Toluene with Methanol: Synergy of External Acid Sites and Diffusion

2025-06-11

X. Zhang , He Han , Jiaxing Zhang +5 more | ACS Catalysis

Probing bimodal sub‐nanopores in carbon for ideal fast sieving separation of propylene/propane

2025-06-10

Xinxin Li , Jiawu Huang , Cuiting Yang +5 more | AIChE Journal

Abstract Rigid molecular sieve is highly desirable in industrial gas separation, but persistently challenged by sluggish adsorption within inherent rigidity‐confined narrow sieving pores. Herein, we report a rigid carbon‐based molecular … Abstract Rigid molecular sieve is highly desirable in industrial gas separation, but persistently challenged by sluggish adsorption within inherent rigidity‐confined narrow sieving pores. Herein, we report a rigid carbon‐based molecular sieve featuring ink‐bottle bimodal sub‐nanopores for the ideal fast sieving separation of propylene/propane mixture. The tailor‐made narrow pore entrance, centered at 5.0 Å, affords precise sieving capacity for propylene over propane with a high selectivity exceeding 200. Concurrently, the larger cavity located at 6.4 Å allows the exceptional fast adsorption kinetics of propylene. The measured diffusion coefficient of propylene (4.2 × 10–3 s −1 ) is one to two orders of magnitude higher than state‐of‐the‐art rigid molecular sieves and comparable to the non‐steric diffusion observed in mesoporous zeolite. High‐purity C 3 H 6 production (>99.2%) is achieved in breakthrough experiments through a single adsorption–desorption cycle. This study paves an avenue to unlock rigid molecular sieves toward advanced separation of challenging gas analogues.

A Machine-Learning-Based Investigation on the Formation and Evolution of Silicic Acid Oligomers Structurally Analogous to Zeolite Building Units

2025-06-05

Xin Liu , Yongbo Zhao , Huimin Guo +1 more | The Journal of Physical Chemistry Letters

A machine-learning (ML) based model that is capable of predicting the formation free energy of a silicic acid oligomer (OSA) with its SMILES string was developed and was used to … A machine-learning (ML) based model that is capable of predicting the formation free energy of a silicic acid oligomer (OSA) with its SMILES string was developed and was used to investigate the formation and evolution of OSAs structurally analogous to zeolite secondary building units and composite building units (S/CBU-OSAs) to understand the mechanistic pathways for the integration of OSAs into zeolites. It was shown that most intermolecular condensation (IEC) and intramolecular condensation (IAC) forming the first cycle in OSAs are exergonic and are the major pathways for OSAs evolution. The exergonicity of an IAC depends strongly on the degree of condensation and distortion. The formation of an S/CBU-OSA is more exergonic than the competing formation of a non-S/CBU-OSA, and the exergonicity would be even greater if it were from a non-S/CBU-OSA. The work highlights the feasibility of using ML-based models to predict reaction thermodynamics and pinpoints the superior thermodynamic stability of S/CBU-OSAs.