DFT investigation of the electronic, optical and photocatalytic properties of S and Cd Codoped SrTiO3 for improved hydrogen production

In this study, we analyzed the electronic, optical, photocatalytic properties of Cd doped, Cd/S codoped, and Cd/2S codoped SrTiO₃ using density functional theory (DFT) with generalized gradient approximation (GGA). Our findings show that doping causes a significant reduction in the band gap, promoting photocatalytic activity under visible light. More specifically, Cd monodoping lowers the effective energy of the forbidden band by approximately 0.45 eV. Similarly, the Cd/S codoping causes a reduction of around 0.92 eV, whereas the Cd/2S codoping causes the greatest reduction, which is 1.05 eV. The analysis of the potentials of the conduction band (CBM) and the valence band (VBM) reveals that they include the redox potentials of water, indicating that these materials are thermodynamically suitable for the photodecomposition of water resulting the production of hydrogen under visible light. • Cd and S Codoping SrTiO 3 optimizes optical and electronic properties, contributing to more efficient hydrogen production. • Reduction of the band gap to 2.15 eV increases the absorption in the solar spectrum. • Improved charge separation for high catalytic efficiency. • This study reveals the prospects for advanced photocatalyst materials.