DFT study of electronic and optical properties of (S-Mn) co-doped SrTiO3 for enhanced photocatalytic hydrogen production

We studied the electronic and optical properties of S-doped, Mn-doped, and S/Mn-codoped SrTiO3 by means of full-potential linearized augmented plane wave method within the density functional theory in its generalized gradient approximation (GGA). Our aim is to explain the physical and chemical origin of the photocatalytic activity observed in experiments under visible light for the monodoping systems, and to provide a theoretical basis for the experimental study for the codoped system. The calculated results show that all dopings lead to band gap narrowing, which enhances the visible light catalytic activity. The monodoping with Mn and S reduces the effective band gap energy by about 0.4 eV and 0.6 eV, respectively. The Mn-S codoped SrTiO3 showed the narrowest band gap (by about 0.9 eV) due to the synergistic effects of Mn and S atoms. The abilities of systems, towards the photocatalytic hydrogen production from water splitting was discussed in the basis of obtained results.