%0 Journal Article
%T Hydrothermal Synthesis and Characterization of Ni-Al Montmorillonite-Like Phyllosilicates
%A Marc X. Reinholdt
%A Jocelyne Brendl¨¦
%A Marie-H¨¦l¨¨ne Tuilier
%A Serge Kaliaguine
%A Emmanuelle Ambroise
%J Nanomaterials
%D 2013
%I MDPI AG
%R 10.3390/nano3010048
%X 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 m 2 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.
%K clay
%K montmorillonite
%K synthesis
%K fluoride medium
%K solid-state NMR
%K EXAFS
%U http://www.mdpi.com/2079-4991/3/1/48