Optimized Synthesis of Ag‐Modified Al‐Doped SrTiO 3 Photocatalyst for the Conversion of CO 2 Using H 2 O as an Electron Donor

Abstract Ag‐modified Al‐doped SrTiO 3 (Ag/Al‐SrTiO 3 ) was fabricated via a flux method and was found to exhibit high efficiency and selectivity toward CO evolution using H 2 O as an electron donor under photoirradiation at wavelengths greater than 300 nm. The fabrication conditions, such as calcination temperature and time, were optimized in this study because these factors had obvious effects on the crystallinity, microstructure, and degree of Al doping of the Al‐SrTiO 3 photocatalysts. The 1.0‐wt.% Ag/Al‐SrTiO 3 photocatalyst fabricated by chemical reduction showed a good rate (5.5 μmol h −1 ) of CO formation. Moreover, excellent selectivity (98.8%) was achieved. Importantly, the O 2 formation rate was 2.7 μmol h −1 , which indicates that the number of estimated holes was equivalent to the number of electrons estimated from the CO formation rate. Thus, H 2 O is the electron donor in this case. In addition, the charge separation in SrTiO 3 was significantly promoted after Ag modification and Al doping, and the Ag cocatalyst particle size and dispersion, as well as the chemical state of Ag, affected the photocatalytic activity.