Revealing and accelerating interfacial charge carrier dynamics in Z-scheme heterojunctions for highly efficient photocatalytic oxygen evolution

Searching for highly efficient photocatalysts for water oxidation is the footstone for the development of overall water splitting systems and has been actively pursued. The construction of artificial Z-scheme heterojunction photocatalysts has been conclusively proven to be effective in boosting charge transport property and in improving the OER performance. Herein, Ag3PO4 particles anchored on modified crispy g-C3N4 flakes have been successfully fabricated. KOH-assisted surface modification of g-C3N4 flakes and intimate interfacial contact favor the accelerated charge transfer and highly improved OER efficiency. Ultrafast spectroscopy results reveal that modified g-C3N4 with crispy nanostructures possesses more trap-induced long-lived photogenerated holes, which are extremely helpful to combine with photo-generated electrons from the conduction band (CB) position of Ag3PO4 via the specific Z-scheme configuration, leaving more holes in the valence band (VB) of Ag3PO4 for the enhanced OER. Superb oxygen-evolving performance highlight the great promise of Z-scheme Ag3PO4-based heterojunctions in solar-driven photocatalytic water splitting.