Surface-phase junctions of branched TiO2 nanorod arrays for efficient photoelectrochemical water splitting

• We synthesized branched TiO2 NRs owning the surface anatase/rutile junctions.
• The flower-like branched TiO2 NRs showed excellent PEC performance response.
• The surface anatase/rutile junctions formed on the boundary of branches and trunks improved the PEC performance.

Flower-like branched TiO2 nanorod arrays (NRs) owning the surface anatase/rutile junctions on FTO substrates with operational diameter were successfully fabricated by a modified hydrothermal method. Transmission electron microscopy, Raman spectroscopy, field emission scanning electron microscopy, and X-ray diffraction revealed a unique flower-like ranched morphology, surface features, a crystal phase, and lattice constant of TiO2. Photoelectrochemical (PEC) measurements showed excellent photocatalytic properties of the flower-like branched TiO2 NRs. The surface phase formed between anatase and rutile TiO2 NRs which efficiently enhances the separation of photo-generated electron–hole pairs and accelerates the transport of charges is the key influence factor. The results suggest that the branched TiO2 NRs owning the surface anatase/rutile junctions are very promising platform to make highly efficient photoanodes for energy devices.

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