Role of indium in tuning the band structure of Sr1-In TiO3 for enhanced photocatalytic water splitting: A GGA + U study

Electronic structures and optical properties of In-doped SrTiO3 (Sr1-xInxTiO3) were systematically analyzed by using first-principles calculations. The calculated formation energies indicate that the Sr1-xInxTiO3 system is stable. Calculated results show that the band gaps of SrTiO3 are significantly reduced when In dopants replace Sr atoms. It is observed that impurity bands formed by the contribution of In-5 s, Ti-3d, and O-2p orbitals appeared in the band gap of the doped system. The photoabsorption spectra and the calculated positions of the band edges indicate that Sr0.875In0.125TiO3 has better visible light absorption activity than pure SrTiO3 and is more suitable for water separation.