Optimized Synthesis of Ag-Modified Al-Doped SrTiO3 Photocatalyst for the Conversion of CO2 Using H2O as an Electron Donor

摘要

Ag-modified Al-doped SrTiO3(Ag/Al-SrTiO3)was fabricated via a flux method and was found to exhibit high efficiency and selectivity toward CO evolution using H2O 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-SrTiO3 photocatalysts.The 1.0-wt.% Ag/Al-SrTiO3 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 O2 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,H2O is the electron donor in this case.In addition,the charge separation in SrTiO3 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.