Effective Driving of Ag-Loaded and Al-Doped SrTiO₃ under Irradiation at λ > 300 nm for the Photocatalytic Conversion of CO₂ by H₂O

Al-doped strontium titanite (Al–SrTiO₃) containing numerous stepwise edges on the surface was found to exhibit an excellent performance in the photocatalytic conversion of CO₂ by H₂O as an electron donor under photoirradiation at >300 nm with Ag modification, while in contrast, the Ag-loaded pristine SrTiO₃ was inactive as a photocatalyst for this reaction. CO was stably evolved as the main reduction product at a rate of 7.2 μmol h^–1 over the Ag-loaded Al–SrTiO₃, and a small amount of H₂ was generated during the three runs. The selectivity of electrons generated by charge transfer toward CO evolution was ∼98.0%. In addition, the stoichiometric formation of O₂ was observed, indicating that H₂O acts as an electron donor for the reduction of CO₂. Furthermore, isotopic experiments performed using ¹³CO₂ revealed that the CO product is derived from CO₂ bubbled into an aqueous solution of NaHCO₃ and not from residual carbon species on the catalyst surface.