Novel Bi-based iodate photocatalysts with high photocatalytic activity

Two novel Bi-based iodates BiIO4 and Bi(IO3)3 with nonbonding layered structures were successfully synthesized via a facile hydrothermal method. The as-prepared samples were characterized by XRD, SEM and DRS. Their optical band gaps and energy levels have been determined, which were also confirmed by the first principle calculations. BiIO4 and Bi(IO3)3 have an indirect and direct transition optical band-gap of 2.94 and 3.58 eV, respectively. The photocatalytic activities of the samples were determined by oxidative decomposition of methyl orange (MO) in aqueous solution. The results revealed that BiIO4 and Bi(IO3)3 display high photocatalytic activity, much better than that of Bi-based photocatalyst Bi2O2CO3. Especially, the photocatalytic efficiency of BiIO4 is about 2.2 times higher than that of commercial TiO2 (P25), though the BET surface is just 1/20 of that of P25. The layered structure should be responsible for the hole–electron separation and transport of charge.