Unveiling the enhanced carrier dynamics of nanoscale stacking fault effect in Al: SrTiO3 for photocatalytic overall water splitting

Modulation of the built-in electric field was one of the effective strategies to enhance the separation of photogenerated carriers. Herein, corner-cut nano-cubic Al: SrTiO 3 was synthesized via the stoichiometric SrCl 2 molten salt regulation strategy. Notably, a rare phenomenon of stacking fault effect in SrTiO 3 , induced by Al 2 O 3 phase transition doping, was discovered. This phenomenon could serve as an effective approach for modulating the built-in electric field within Al:SrTiO 3 , and the photocarrier lifetime could be prolonged to exceed 2500 ps after investigated by the femtosecond ultrafast spectroscopy, which could be ascribed to the hole capture by Al 3+ through TiO 6 polarizability regulation. Consequently, compared to samples without stacking fault effect, the optimized Al: SrTiO 3 photocatalysts demonstrated an enhanced STH efficiency increasing from 0.15 % to 0.5 %. This work revealed the phenomenon of stacking fault effect in nano-photocatalysts and proposed insights into the mechanisms of the built-in electric field regulation through microstructure polarization.