The effects of In3+ doping on the properties of precipitated goethite

Indium-doped goethite samples were synthesized by the precipitation method at pH 12 using an organic alkali tetramethylammonium hydroxide (TMAH) and investigated using different instrumental techniques. In3+-for-Fe3+ substitution in the goethite structure was confirmed by the measurement of the unit cell expansion by XRD and the reduction of the hyperfine magnetic field by Mössbauer spectroscopy. Maximum substitution was estimated at about 8 mol%. Indium substitution in goethite also caused an increase in the size of crystallites and particles, a shift in the position of bands in FT-IR and UV-Vis-NIR spectra and a rise in goethite dehydroxylation temperature (observed by TGA-DTA).