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

Titanium dioxide (TiO2)-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 TiO2-graphene-Ta3N5 hybrid photocatalyst synthesized via an ultrasonic-hydrothermal method. Compared with pristine TiO2 and Ta3N5, the prepared TiO2-graphene-Ta3N5 present remarkably enhanced photocatalytic pure water splitting behavior with an optimal H-2-evolution rate of 180 mu mol 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 TiO2 to Ta3N5. This work opens avenues to design efficient TiO2-based photocatalyst by embedding conducting layer for rapid electron transfer during solar fuel conversion.

Automated summary

This study reports the synthesis of a titanium dioxide-graphene-tantalum nitride hybrid photocatalyst through an ultrasonic-hydrothermal method. Compared to pristine titanium dioxide and tantalum nitride, the prepared hybrid photocatalyst exhibits significantly enhanced performance in photocatalytic water splitting, attributed to improved visible light utilization and charge transfer behavior. It was found that water splitting is achieved through a Z-scheme mechanism, with graphene acting as a bridge for electron transfer between titanium dioxide and tantalum nitride.