Abstract

The influence of Ti(IV) on the formation and structure of α-FeOOH particles was investigated by characterizing the coprecipitation products of Fe(III) with Ti(IV) at different atomic ratios (Ti/Fe) in the range 0–0.1. The particle width of the products increased as Ti/Fe was increased. At Ti/Fe ≥ 0.05 the crystallite size of α-FeOOH increased with increase of Ti/Fe while the XRD peaks decreased in intensity. Thermal analysis and Mössbauer spectroscopy showed that the α-FeOOH phase diminishes upon doping with Ti(IV) and that less crystalline regions composed of agglomerates of fine particles develop. EXAFS revealed that the doped Ti(IV) disturbs the nearest coordination structure surrounding Fe(III). According to N₂ adsorption, micropores are formed in the particles upon addition of Ti(IV). It is deduced from the obtained results that the addition of Ti(IV) produces double domain particles consisting of an α-FeOOH core and a porous poorly crystalline shell.