DFT study of Se/Mn and Te/Mn codoped SrTiO3 for visible light-driven photocatlytic hydrogen production

It is interesting to tune the band gap energy of SrTiO3 to harvest solar light for efficient photocatalytic hydrogen evolution. Commonly, doping is considered as promising way for band-gap engineering, due to its simplicity, effectiveness and low cost. In this theoretical research, we will demonstrate that codoping with tellurium and manganese is a promising way to alter the electronic structure and the absorption properties of SrTiO3 to increase its photocatalytic performance in the visible light range. Our results show that codoping with Se/Mn decreases the effective band gap energy of SrTiO3 by about 0.96 eV, while codoping with Te/Mn narrows significantly the band gap (by about 1.61eV), leading to an enormous absorption spectrum red-shifting. Besides, our findings show that the conduction band and valence band positions of SrTiO3 are optimized through Te/Mn codoping, in a way that makes the best use of its potential. •Spin-polarized DFT-GGA calculations of electronic, optical and photocatalytic properties for Se/Mn and Te/Mn codoped SrTiO3is performed.•The defect formation energies are calculated..•The optical properties indicate that Te/Mn codoped SrTiO3 improves the visible-light photo-catalytic activity.•The photocatalytic generation of hydrogen from water splitting using visible light irradiation was discussed.