Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Keggin-Al30: An intercalant for Keggin-Al30 pillared montmorillonite
https://orcid.org/0000-0002-2080-6541
https://orcid.org/0000-0002-7057-7687
https://orcid.org/0000-0002-9002-4457
https://orcid.org/0000-0003-2924-9494
Abstract Clay minerals intercalated with inorganic species, known as pillared interlayered clays, have received extensive attention in recent decades. In this work, by comparison with those of Keggin-Al13, the formation processes of Keggin-Al30 are discussed based on different hydrolysis reactions. X-ray diffraction (XRD), field-emission scanning electron microscope, and thermogravimetric analyses were applied to compare differences in crystal structure, morphology, and thermal stability between Keggin-Al13 and Keggin-Al30 (sulfates). High temperature and excess monomeric Al species are key factors controlling the transformation from ε-Keggin-Al13 to δ-Keggin-Al13 and finally to Keggin-Al30. A decrease of the crystal symmetry from Keggin-Al13 to Keggin-Al30 was confirmed by shifts of reflections (and decreases of intensities) on XRD patterns. Keggin-Al30 has a more compact structure, which leads to higher thermal stability. The distributions of functional groups and positive charges on the surface of Keggin-Al30 result in a “lying flat” arrangement configuration in the interlayer region of montmorillonite. Exploring the behaviors of polycations as intercalants from their formation, transformation, and properties during the pillaring process may offer better understandings of the enhanced properties and wide applications of pillared interlayered clays.
Graphical abstract Display Omitted
Highlights (111) reflection in Keggin-Al30 XRD patterns shifts to a lower 2θ because of the relatively lower symmetry of Keggin-Al30 High density of positive charges on the waist of Keggin-Al30 results in its specific “lying flat” arrangement in Mt. The higher thermal stability of Keggin-Al30 than Keggin-Al13 is caused by the more compacted structure of Keggin-Al30.
Keggin-Al30: An intercalant for Keggin-Al30 pillared montmorillonite
https://orcid.org/0000-0002-2080-6541
https://orcid.org/0000-0002-7057-7687
https://orcid.org/0000-0002-9002-4457
https://orcid.org/0000-0003-2924-9494
Abstract Clay minerals intercalated with inorganic species, known as pillared interlayered clays, have received extensive attention in recent decades. In this work, by comparison with those of Keggin-Al13, the formation processes of Keggin-Al30 are discussed based on different hydrolysis reactions. X-ray diffraction (XRD), field-emission scanning electron microscope, and thermogravimetric analyses were applied to compare differences in crystal structure, morphology, and thermal stability between Keggin-Al13 and Keggin-Al30 (sulfates). High temperature and excess monomeric Al species are key factors controlling the transformation from ε-Keggin-Al13 to δ-Keggin-Al13 and finally to Keggin-Al30. A decrease of the crystal symmetry from Keggin-Al13 to Keggin-Al30 was confirmed by shifts of reflections (and decreases of intensities) on XRD patterns. Keggin-Al30 has a more compact structure, which leads to higher thermal stability. The distributions of functional groups and positive charges on the surface of Keggin-Al30 result in a “lying flat” arrangement configuration in the interlayer region of montmorillonite. Exploring the behaviors of polycations as intercalants from their formation, transformation, and properties during the pillaring process may offer better understandings of the enhanced properties and wide applications of pillared interlayered clays.
Graphical abstract Display Omitted
Highlights (111) reflection in Keggin-Al30 XRD patterns shifts to a lower 2θ because of the relatively lower symmetry of Keggin-Al30 High density of positive charges on the waist of Keggin-Al30 results in its specific “lying flat” arrangement in Mt. The higher thermal stability of Keggin-Al30 than Keggin-Al13 is caused by the more compacted structure of Keggin-Al30.
Keggin-Al30: An intercalant for Keggin-Al30 pillared montmorillonite
https://orcid.org/0000-0002-2080-6541
https://orcid.org/0000-0002-7057-7687
https://orcid.org/0000-0002-9002-4457
https://orcid.org/0000-0003-2924-9494
Abstract Clay minerals intercalated with inorganic species, known as pillared interlayered clays, have received extensive attention in recent decades. In this work, by comparison with those of Keggin-Al13, the formation processes of Keggin-Al30 are discussed based on different hydrolysis reactions. X-ray diffraction (XRD), field-emission scanning electron microscope, and thermogravimetric analyses were applied to compare differences in crystal structure, morphology, and thermal stability between Keggin-Al13 and Keggin-Al30 (sulfates). High temperature and excess monomeric Al species are key factors controlling the transformation from ε-Keggin-Al13 to δ-Keggin-Al13 and finally to Keggin-Al30. A decrease of the crystal symmetry from Keggin-Al13 to Keggin-Al30 was confirmed by shifts of reflections (and decreases of intensities) on XRD patterns. Keggin-Al30 has a more compact structure, which leads to higher thermal stability. The distributions of functional groups and positive charges on the surface of Keggin-Al30 result in a “lying flat” arrangement configuration in the interlayer region of montmorillonite. Exploring the behaviors of polycations as intercalants from their formation, transformation, and properties during the pillaring process may offer better understandings of the enhanced properties and wide applications of pillared interlayered clays.
Graphical abstract Display Omitted
Highlights (111) reflection in Keggin-Al30 XRD patterns shifts to a lower 2θ because of the relatively lower symmetry of Keggin-Al30 High density of positive charges on the waist of Keggin-Al30 results in its specific “lying flat” arrangement in Mt. The higher thermal stability of Keggin-Al30 than Keggin-Al13 is caused by the more compacted structure of Keggin-Al30.
Keggin-Al30: An intercalant for Keggin-Al30 pillared montmorillonite
Wen, Ke (Autor:in) / Wei, Jingming (Autor:in) / He, Hongping (Autor:in) / Zhu, Jianxi (Autor:in) / Xi, Yunfei (Autor:in)
Applied Clay Science ; 180
24.06.2019
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Heteropolyacids with Keggin structure supported on silica-alumina
| British Library Online Contents | 2006
Heteropolyacids with Keggin structure supported on silica-alumina
| British Library Online Contents | 2006
A Mixed Valent Keggin Polyoxometallate Involving Molybdenum and Tungsten
| British Library Online Contents | 1995