Abstract: This work describes the first hydrothermal synthesis in fluoride medium of Ni-Al montmorillonite-like phyllosilicates, in which the only metallic elements in the octahedral sheet are Ni and Al. X-ray diffraction, chemical analysis, thermogravimetric and differential thermal analysis, scanning electron microscopy and transmission electron microscopy confirm that the synthesized samples are montmorillonite-like phyllosilicates having the expected chemical composition. The specific surface areas of the samples are relatively large (>100 m2 g−1) compared to naturally occurring montmorillonites. 29Si and 27Al nuclear magnetic resonance (NMR) indicate substitutions of Al for Si in the tetrahedral sheet. 19F NMR and Ni K-edge extended X-ray absorption fine structure (EXAFS) local probes highlight a clustering of the metal elements and of the vacancies in the octahedral sheet of the samples. These Ni-Al phyllosilicates exhibit a higher local order than in previously synthesized Zn-Al phyllosilicates. Unlike natural montmorillonites, where the distribution of transition metal cations ensures a charge equilibrium allowing a stability of the framework, synthetic montmorillonites entail clustering and instability of the lattice when the content of divalent element in the octahedral sheet exceeds ca. 20%. Synthesis of Ni-Al montmorillonite-like phyllosilicates, was successfully achieved for the first time. These new synthetic materials may find potential applications as catalysts or as materials with magnetic, optical or staining properties.
Keywords: clay; montmorillonite; synthesis; fluoride medium; solid-state NMR; EXAFS
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Reinholdt, M.X.; Brendlé, J.; Tuilier, M.-H.; Kaliaguine, S.; Ambroise, E. Hydrothermal Synthesis and Characterization of Ni-Al Montmorillonite-Like Phyllosilicates. Nanomaterials 2013, 3, 48-69.
Reinholdt MX, Brendlé J, Tuilier M-H, Kaliaguine S, Ambroise E. Hydrothermal Synthesis and Characterization of Ni-Al Montmorillonite-Like Phyllosilicates. Nanomaterials. 2013; 3(1):48-69.
Reinholdt, Marc X.; Brendlé, Jocelyne; Tuilier, Marie-Hélène; Kaliaguine, Serge; Ambroise, Emmanuelle. 2013. "Hydrothermal Synthesis and Characterization of Ni-Al Montmorillonite-Like Phyllosilicates." Nanomaterials 3, no. 1: 48-69.