Manipulating a TiO2-graphene-Ta3N5 heterojunction for efficient Z-scheme photocatalytic pure water splitting.

• TiO 2 -graphene-Ta 3 N 5 can be fabricated by ultrasonic-hydrothermal method. • Graphene at the interface contributes to fluent charge transfer. • Improved photocatalytic activity is achieved via a Z-scheme mechanism. • Photocatalytic pure water splitting is experimentally demonstrated. Titanium dioxide (TiO 2)-based photocatalysts are a class of hottest materials in solar water splitting, while limited achievements have been gained to date due to its broad band-gap only responding in UV region and sluggish charge transfer. Here, we reported a ternary TiO 2 -graphene-Ta 3 N 5 hybrid photocatalyst synthesized via an ultrasonic-hydrothermal method. Compared with pristine TiO 2 and Ta 3 N 5 , the prepared TiO 2 -graphene-Ta 3 N 5 present remarkably enhanced photocatalytic pure water splitting behavior with an optimal H 2 -evolution rate of 180 μmol h−1 g−1. In conjunction with systematic characterizations, we demonstrated the boosted photocatalytic performance is ascribed to both improved visible light utilization and charge transfer behavior. Particularly, it is found that water splitting is achieved through a Z-scheme mechanism, in which the two-dimensional lamellar graphene served as a bridge accelerating the electron transfer from TiO 2 to Ta 3 N 5. This work opens avenues to design efficient TiO 2 -based photocatalyst by embedding conducting layer for rapid electron transfer during solar-fuel conversion. Graphiocal Abstract [Display omitted] [ABSTRACT FROM AUTHOR]