The application of semiconductor photocatalysts with narrow band gaps is hindered by the rapid recombination of electron-hole pairs and limitation of multiple reactive oxygen species (ROS) synchronous generation. A n-n-type direct Z-scheme heterostructured photocatalyst was constructed based on the staggered band alignment of bismuth tungstate (Bi2WO6) and indium zinc sulfide (ZnIn2S4) to reveal the synergistic effect of charge separation and multiple ROS synchronous generation on boosting photocatalytic performance. Under irradiation, electrons in the conduction band (CB) of Bi2WO6 and holes in the valence band (VB) of ZnIn2S4 recombined at interface to prolong the lifetime of electrons in the CB of ZnIn2S4 and holes in the VB of Bi2WO6. Meanwhile, the multiple ROS synchronously generated to oxidize pollutant due to the strong redox ability of electrons of ZnIn2S4 and holes of Bi2WO6, which was determined by the CB potential of ZnIn2S4 and VB potential of Bi2WO6. The results provided valuable insights for the application of photocatalysts with a narrow band gap in the field of water pollution control.
Keywords: charge separation; direct Z-scheme heterojunction; photocatalysis; photoelectrochemical property; redox ability.