TiO2/Cu2O Core/Ultrathin Shell Nanorods as Efficient and Stable Photocatalysts for Water Reduction

P-type Cu2O has been long considered as an attractive photocatalyst for photocatalytic water reduction, but few successful examples has been reported. Here, we report the synthesis of TiO2 (core)/Cu2O (ultrathin film shell) nanorods by a redox reaction between Cu2+ and in-situ generated Ti3+ when Cu2+-exchanged H-titanate nanotubes are calcined in air. Owing to the strong TiO2-Cu2O interfacial interaction, TiO2 (core)/Cu2O (ultrathin film shell) nanorods are highly active and stable in photocatalytic water reduction. The TiO2 core and Cu2O ultrathin film shell respectively act as the photosensitizer and cocatalyst, and both the photoexcited electrons in the conduction band and the holes in the valence band of TiO2 respectively transfer to the conduction band and valence band of the Cu2O ultrathin film shell. Our results unambiguously show that Cu2O itself can act as the highly active and stable cocatalyst for photocatalytic water reduction.