BiFeO3–BaTiO3 solid solutions with dielectric-screened charge separation for photocatalytic H2 production under visible light

BiFeO 3 is a narrow-bandgap semiconductor promising for solar water splitting but is generally subject to a low photocatalytic activity due to the poor separation of photocarriers (e − and h + ). In this work, BiFeO 3 has been combined with BaTiO 3 to form the solid solutions (i.e. (BiFeO 3 ) 1-x (BaTiO 3 ) x (0 ≤ x ≤ 1)) which demonstrate a much-improved activity for photocatalytic H 2 production under visible light illumination. The solid solution strategy not only tunes the bandgap but also modifies the dielectric constant that is critical for a high photocatalytic activity. A high dielectric constant contributes to an improved photocarrier separation condition due to the screening of the Coulomb interactions between photocarriers and between photocarriers and charged defects. This work reveals a useful solid solution strategy to modify the photocatalytic performance and justifies the importance of dielectric properties for photocarrier separation.