Boosting Light‐Driven Photocatalytic Water Splitting of Bi4NbO8Br by Polarization Field

Photocatalysis is regarded as a promising approach to solve the energy crisis by producing H 2 from water splitting reaction driven by solar light. However, low photogenerated charge carriers yielding and separating rates limit the quantum efficiency in photocatalytic reactions, which is a common drawback for most visible‐light photocatalysts. Herein, a bismuth‐based photocatalyst, Bi 4 NbO 8 Br, through intercalating NbO 6 octahedrons into layered BiOBr nanosheets, is designed and fabricated. Bi 4 NbO 8 Br demonstrates an enhanced photocatalytic water splitting ability as compared to BiOBr in visible light irradiation. The light absorption spectrum of Bi 4 NbO 8 Br is wider than that of BiOBr. It is found that such enhancements give rise to the ferroelectricity induced by the intercalated NbO 6 . The internal spontaneous polarization and an internal electric field formed in Bi 4 NbO 8 Br result in a significant band bending in its electronic structure and greatly promote the migration and separation of charge carriers in visible light irradiation.