First principles insight on enhanced photocatalytic performance of sulfur-doped bismuth oxide iodate

Bismuth oxide iodate photocatalyst is mostly limited in photocatalytic applications due to its large band gap. Doping by metal and nonmetal ions is one of the simplest and most effective ways to solve the problem. The effect mechanism of nonmetallic sulfur atoms doping on the BiOIO3 semiconductor was studied via the first principles of density functional theory (DFT). A series of doping sites were determined, and the differences in energy band structure, density of states, and light absorption spectra of BiOIO3crystals after sulfur doping were carefully investigated. The doping of any oxygen site may cause the crystal conduction band position to move down, reduce the energy band gap, and the energy required for electron transition is easier to meet, which enhances the photocatalytic activity of the semiconductor. Iodine site doping gives a more reasonable crystal formation energy than substituting oxygen site doping. Moreover, the crystal with iodine doping will introduce obvious impurity states around the Fermi level, and the impurity level can act as a bridge for the electron transition. This work is also helpful in understanding the improvement of photocatalytic performance through crystal doping modification.