Facile synthesis and characterization of pure tochilinite‐like materials from nanoparticulate FeS

Abstract

In this work, three different tochilinite‐like materials have been obtained by sophisticated synthetic methods that allow to control the distribution of iron ions. The purity of the samples was confirmed by powder X‐ray diffraction. From elemental analysis and Mössbauer spectroscopy data, detailed compositions could be determined: T1) Fe0.76S*0.86 [Fe2+0.01Fe3+0.56Mg2+0.43(OH)2.01]; T2) Fe0.89S*0.85 [Fe2+0.55Fe3+0.11Al3+0.33(OH)1.84(O)0.16]; T3) Fe0.71S*0.79 [Fe2+0.25Fe3+0.73Mg2+0.01Al3+0.01(OH)1.98(O)0.02]. These compositions fit to typical compositions of tochilinite in regard of the amount of iron vacancies and the volume ratio of the hydroxide layers to the sulfide layers. Besides hydroxide ions, oxide ions are also present in the hydroxide layers as a result of surface oxidation after the synthesis due to the high reactivity of the particles. TEM and SEM investigations show that the obtained powders consist mainly of thin sheets accompanied by nanotubes with BET surface areas ranging between 20 m2/g and 40 m2/g. The thermal stability was investigated by TGA and DSC analysis and it depends significantly on the composition.