Facile fabrication of three-dimensional interconnected nanoporous N-TiO2 for efficient photoelectrochemical water splitting

Three-dimensional (3D) interconnected porous architectures are expected to perform well in photoelectrochemical (PEC) water splitting due to their high specific surface area as well as favourable porous properties and interconnections. In this work, we demonstrated the facile fabrication of 3D interconnected nanoporous N-doped TiO2 (N-TiO2 network) by annealing the anodized 3D interconnected nanoporous TiO2 (TiO2 network) in ammonia atmosphere. The obtained N-TiO2 network exhibited broadened light absorption, and abundant, interconnected pores for improving charge separation, which was supported by the reduced charge transfer resistance. With these merits, a remarkably high photocurrent density at 1.23 V vs. reversible hydrogen electrode (RHE) was realized for the N-TiO2 network without any co-catalysts or sacrificial reagents, and the photostability can be assured after long term illumination. In view of its simplicity and efficiency, this structure promises for perspective PEC applications.