Synthesis, characterization and application of iodine modified titanium dioxide in phototcatalytical reactions under visible light irradiation

► I-TiO2 nanoparticles were prepared by simple hydrolysis calcination method. ► Iodine exists in two different states assigned to I5+ and I− in I-TiO2. ► I5+ was doped in the lattice while I− was dispersed on the surface of the catalyst. ► I-TiO2 degraded AO7, 2,4-DCP and MO under visible light effectively. ► AO7 degradation followed indirect oxidation via hydroxyl radicals.