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.