Synergistic Sn/Cr Co-Doping in SrTiO3 for Enhanced Visible-Light-Driven Overall Photocatalytic Water Splitting

Developing efficient visible-light-driven photocatalysts for overall water splitting remains a significant challenge. Herein, Sn/Cr co-doped SrTiO 3 (SCSTO) was synthesized via a flux-assisted solid-state reaction, with Sn substituting Sr sites and Cr replacing Ti sites in the perovskite lattice. Sn/Cr synergistic co-doping extends optical absorption into the visible region, narrows the bandgap to 3.04 eV, suppresses Ti3+ defects and oxygen vacancies, and promotes charge separation and migration. Benefiting from the rational band structure and defect engineering, under visible-light irradiation (λ > 380 nm), the optimal SCSTO exhibits a hydrogen evolution rate of 15.4 µmol·h − 1 and oxygen evolution rate of 7.34 µmol·h −1 , with outstanding cycling stability. DFT calculations confirm that Cr 3d mid-gap states below the Ti 3d conduction band enhance visible-light response and charge transfer. This work provides a universal and feasible co-doping strategy for designing high-performance perovskite oxide photocatalysts toward efficient solar fuel production, which is instructive for the development of advanced visible-light-driven photocatalytic systems. Graphical A synergistic Sn/Cr dual-site co-doping strategy was developed for SrTiO 3 to enable efficient visible-light-driven overall water splitting.