Insight into the enhanced photocatalytic activity of Mo and P codoped SrTiO₃ from first-principles prediction

In this study, the synergistic effect of cation codoping (Mo and the cation P) on the band structure of SrTiO₃ is demonstrated to enhance its photocatalytic activity. The electronic structure and optical properties of (Mo + P) codoped SrTiO₃ are examined by performing GGA + U calculations. The results show that the strong hybridization between the Mo 4d states and the O 2p states assisted by the non-metal P leads to the formation of fully occupied and delocalized intermediate states (IBs) near the valence band of SrTiO₃. The proximity of IBs to the valence band resulted in the ability to separate photo-excited electrons from reaction holes, which helps to ensure efficient electron replenishment reducing the probability of trapping electrons from the CB. This kind of metal Mo and non-metal P-compensated codoping can efficiently narrow the band gap and enhance the visible-light absorption. Moreover, the positions of the band edges after codoping (Mo + P) are found to be thermodynamically favorable for water splitting.