Heavy atom perturbation by the incorporation of iodine ion into BaTiO3 lattice: Reduction of fluorescence and enhancement of rate of interfacial charge transfer process under the visible light irradiation

Abstract

Iodine was incorporated into the BaTiO3 (BTO) lattice in the concentration range of 0.3-0.9 wt. % and the photocatalytic activities were tested for the degradation of congo red (CR) as a model compound under visible light irradiation. The doped iodine (I5+) plays a major role in improving the efficiency of the charge transfer dynamics of the system. I5+ is substituted at Ti4+ site in BTO lattice and it extends the photoresponse of the catalyst to the visible light range. 0.7 wt. % of I doped photocatalyst shows high photocatalytic activity due to the synergistic effects that include optimum dopant concentration, enhanced visible light absorption, efficient charge carrier separation. I induced dopant energy level facilitates the absorption of visible light and the excitation of electrons takes place from the valence band (VB) to the dopant energy level. I being a heavy atom can perturb the fluorescence process and in turn increases the lifetime of the photogenerated charge carriers. The active role of hole, hydroxyl radical and superoxide radicals in the degradation reaction was determined by the addition of scavengers like methanol (hydroxyl radical scavenger), benzoquinone (superoxide radical scavenger) and oxalic acid (hole scavenger).