A doping model of homogeneous photocatalysts of TiO2 is constructed to directly show the mapping relationship between carrier separation efficiency and photocatalytic performance. TRPL, KPFM, fs-TAS measurements further quantify the carrier dynamics process. The photocatalytic performance of this series samples is dominated by the optimal conditions of carrier separation behaviour within a certain range, and does not form a linear dependence on the site, the oxygen vacancy.
Abstract
Homogeneous matrix materials are considered to be a solid guarantee of site-point charge transfer reactions because they are the main body of light absorption, photogenerated carrier separation, migration, and recombination processes. Elucidating the effect of carrier separation efficiency on catalytic performance is of great significance for overcoming the optimization obstacles of homogeneous matrix parts and providing new design strategies. In this study, TiO2 doped with Fe as the research object quantifies the carrier dynamics while trying to avoid large site and lattice changes. The direct correlation between carrier separation efficiency and photocatalytic performance with different doping content samples is clearly elucidated by carrier dynamic characterization results. Doping of 0.213 wt.% Fe exhibits the best catalytic performance, achieving CO yield of 35.12 µmol g−1 h−1. Especially, the femtosecond transient absorption spectroscopy demonstrates the defect level formed by doping Fe enhances the separation of photogenerated electrons. The clear relationship shown above, which is catalytic capacity mapping with carrier separation efficiency, rather than a linear dependence on sites and oxygen vacancies, fully demonstrates the great potential of simple doping strategies for homogeneous photocatalysts.
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