Application of the 121Sb Mössbauer spectroscopy to characterizing titania-based photocatalysts modified by lone pair cations

A study of the reaction of white light photocatalytic bleaching of methyl orange solutions in the presence of antimony- modified anatase TiO₂ catalysts has revealed a nearly 5-fold increase in the reaction rate constant k in comparison with k₀ for the undoped reference TiO₂. Analysis of ¹²¹Sb spectra has shown that this effect is due to the stereoactive electronic lone pair E of Sbiii species. Our experiments have thus confirmed the mechanism of its positive modifying action theoretically predicted earlier for the isoelectronic lone pair dopant Sn^II.