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  • Wiley  (4)
  • Peng, Mingming  (4)
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  • Wiley  (4)
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  • 1
    Online Resource
    Online Resource
    Breaking Structural Energy Constraints: Hydrothermal Crystallization of High‐Silica Germanosilicates by a Building‐Unit Self‐Growth Approach
    Wiley ; 2018
    In:  Chemistry – A European Journal Vol. 24, No. 50 ( 2018-09-06), p. 13297-13305
    Details
    In: Chemistry – A European Journal, Wiley, Vol. 24, No. 50 ( 2018-09-06), p. 13297-13305
    Abstract: Zeolites, a class of crystalline microporous materials, have a wide range of practical applications, in particular serving as key catalysts in petrochemical and fine‐chemical processes. Millions of zeolite topologies are theoretically possible. However, to date, only 235 frameworks with various tetrahedral element compositions have been discovered in nature or artificially synthesized, among which approximately 50 topologies are available in pure‐silica forms. Germanosilicates are becoming an important zeolite family, with a rapidly increasing number of topological structures having unusual double four‐membered ring (D4R) building units and large‐pore or extra‐large‐pore systems. The synthesis of their high‐silica analogues with higher (hydro)thermal stability remains a great challenge, because the formation of siliceous D4R units is kinetically and thermodynamically unfavorable in hydrothermal systems. Herein, it is demonstrated that such D4R‐containing high‐silica zeolites with unexpected crystalline topologies (ECNU‐24‐RC and IM‐20‐RC) are readily constructed by a versatile route. This strategy provides new opportunities for the synthesis of high‐silica zeolite catalysts that are hardly obtainable by conventional hydrothermal synthesis and may also facilitate a breakthrough in increasing the number and types of zeolite materials with practical applications.
    Type of Medium: Online Resource
    ISSN: 0947-6539 , 1521-3765
    URL: Issue
    URL: Article
    DOI: 10.1002/chem.v24.50
    DOI: 10.1002/chem.201802255
    RVK:
    VA 1120 ; VA 3507
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 1478547-X
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    Online Resource
  • 2
    Online Resource
    Online Resource
    ECNU‐13: A High‐Silica Zeolite with Three‐Dimensional and High‐Connectivity Multi‐Pore Structures for Selective Alkene Cracking
    Wiley ; 2023
    In:  Angewandte Chemie International Edition Vol. 62, No. 15 ( 2023-04-03)
    Details
    In: Angewandte Chemie International Edition, Wiley, Vol. 62, No. 15 ( 2023-04-03)
    Abstract: A high‐silica zeolite ECNU‐13 (Si/Al=23) with a new three‐dimensional (3D) pore system and a nanosized morphology has been developed, consisting of multitudes of 10‐membered ring (10‐R) medium pores and one set of 8‐R small pores. A phase‐discrimination strategy was proposed to synthesize ECNU‐13 by regulating the gel compositions and nucleation processes that were used for preparing 12‐R large‐pore germanosilicate IM‐20 with the known UWY topology. The crystallization was directed towards forming one set of single four‐ring ( s4r ) composite building units together with one set of double four‐ring ( d4r) rather than two different types of d4r units in IM‐20. The electron crystallographic investigations elucidated that the ECNU‐13 structure was composed of two kinds of polymorphs as a result of distinct atomic positionings in s4r units. In catalytic cracking of 1‐butene, ECNU‐13 exhibited high propene selectivity (55.6 %) and propene to ethylene molar ratio ( 〉 4.7) superior to well‐studied conventional ZSM‐5 zeolite catalyst.
    Type of Medium: Online Resource
    ISSN: 1433-7851 , 1521-3773
    URL: Issue
    URL: Article
    DOI: 10.1002/anie.v62.15
    DOI: 10.1002/anie.202217004
    RVK:
    VA 2100
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2011836-3
    detail.hit.zdb_id: 123227-7
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    Online Resource
  • 3
    Online Resource
    Online Resource
    Topotactic Conversion of Alkali‐Treated Intergrown Germanosilicate CIT‐13 into Single‐Crystalline ECNU‐21 Zeolite as Shape‐Selective Catalyst for Ethylene Oxide Hydration
    Wiley ; 2019
    In:  Chemistry – A European Journal Vol. 25, No. 17 ( 2019-03-21), p. 4520-4529
    Details
    In: Chemistry – A European Journal, Wiley, Vol. 25, No. 17 ( 2019-03-21), p. 4520-4529
    Abstract: The conversion of the alkali‐treated intergrowth germanosilicate CIT‐13 into the single‐crystalline high‐silica ECNU‐21 (named after East China Normal University) zeolite, with a novel topology and a highly crystalline zeolite framework, has been realized through a creative top‐down strategy involving a mild alkaline‐induced multistep process consisting of structural degradation and reconstruction. Instead of acid treatment, hydrolysis in aqueous ammonia solution not only readily cleaved the chemically weak Ge(Si)−O−Ge bonds located within the interlayer double four ring (D4R) units of CIT‐13, but also cleaved the metastable Si−O−Si bonds therein. This led to extensive removal of the D4R units, and also generated silanol groups on adjacent silica‐rich layers, which then condensed to form a novel daughter structure upon calcination. Individual oxygen bridges in the reassembled ECNU‐21 replaced the germanium‐rich D4R units in CIT‐13, thereby eliminating the original intergrowth phenomenon along the b axis. With an ordered crystalline structure of 10‐ring (R) channels as well as suitable germanium‐related Lewis acid sites, ECNU‐21 serves as a stable solid Lewis acid catalyst for the shape‐selective hydration of ethylene oxide (EO) to ethylene glycol (EG) at greatly reduced H 2 O/EO ratios and reaction temperature in comparison with the noncatalytic industrial process.
    Type of Medium: Online Resource
    ISSN: 0947-6539 , 1521-3765
    URL: Issue
    URL: Article
    DOI: 10.1002/chem.v25.17
    DOI: 10.1002/chem.201900173
    RVK:
    VA 1120 ; VA 3507
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 1478547-X
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    Online Resource
  • 4
    Online Resource
    Online Resource
    ECNU‐13: A High‐Silica Zeolite with Three‐Dimensional and High‐Connectivity Multi‐Pore Structures for Selective Alkene Cracking
    Wiley ; 2023
    In:  Angewandte Chemie Vol. 135, No. 15 ( 2023-04-03)
    Details
    In: Angewandte Chemie, Wiley, Vol. 135, No. 15 ( 2023-04-03)
    Abstract: A high‐silica zeolite ECNU‐13 (Si/Al=23) with a new three‐dimensional (3D) pore system and a nanosized morphology has been developed, consisting of multitudes of 10‐membered ring (10‐R) medium pores and one set of 8‐R small pores. A phase‐discrimination strategy was proposed to synthesize ECNU‐13 by regulating the gel compositions and nucleation processes that were used for preparing 12‐R large‐pore germanosilicate IM‐20 with the known UWY topology. The crystallization was directed towards forming one set of single four‐ring ( s4r ) composite building units together with one set of double four‐ring ( d4r) rather than two different types of d4r units in IM‐20. The electron crystallographic investigations elucidated that the ECNU‐13 structure was composed of two kinds of polymorphs as a result of distinct atomic positionings in s4r units. In catalytic cracking of 1‐butene, ECNU‐13 exhibited high propene selectivity (55.6 %) and propene to ethylene molar ratio ( 〉 4.7) superior to well‐studied conventional ZSM‐5 zeolite catalyst.
    Type of Medium: Online Resource
    ISSN: 0044-8249 , 1521-3757
    URL: Issue
    URL: Article
    DOI: 10.1002/ange.v135.15
    DOI: 10.1002/ange.202217004
    RVK:
    VA 2100
    RVK:
    VN 5020
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 505868-5
    detail.hit.zdb_id: 506609-8
    detail.hit.zdb_id: 514305-6
    detail.hit.zdb_id: 505872-7
    detail.hit.zdb_id: 1479266-7
    detail.hit.zdb_id: 505867-3
    detail.hit.zdb_id: 506259-7
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