New acetate-intercalated CoNiFe, ZnNiFe and CoZnFe layered double hydroxides: Synthesis by hydrolysis in polyol medium and characterization

Abstract

New layered double hydroxides (LDHs) CoNiFe, ZnNiFe and CoZnFe with M^II/M^III molar ratio of 3, with acetate ions in the interlayer region have been prepared by forced  hydrolysis in polyol medium.

The physico-chemical properties of all products were characterized by the methods of powder X-ray Diffraction, Infrared Spectroscopy, UV-Spectroscopy, Elemental analysis, Thermal analysis, Transmission Electron Microscopy and Scanning Electron Microscopy.

It was found that all compounds present the typical features of hydrotalcite-like structure and exhibit a turbostratic character.

The insertion of acetate anions into LDHs was confirmed and the interlayer spacing values were respectively 12.47, 13.64 and 14.69 Ã… for CoNiFe, ZnNiFe and CoZnFe.

We notice that there is a difference between the interlayer spacing for all synthesized phases with and without zinc. This can be explained by a structural modification on the level of the layers and/ or different arrangement from the inserted species (anions + water) in the interlayer space for zinc materials.

⁵⁷Fe Mössbauer spectrometry allows concluding the presence of Fe³⁺ cations which occupy octahedral sites and confirming the absence of Fe²⁺ in the as-prepared compounds.