Vanadium-doped tantalum nitride sensitized/protected by polyaniline (V-Ta3N5/PANI) was successfully synthesized for efficient photocatalytic water splitting under visible light. The vanadium was used as a dopant incorporated into the Ta3N5 lattice, where it acted as an intermediate band between the valence band and the conduction band of Ta3N5 to narrow the band gap energy of Ta3N5. This intermediate band of the V dopant also enhanced the electron-hole pair separation efficiency and prevented the recombination of the generated electrons and holes, thereby extending the lifetime of the electron-hole pairs. PANI, a conducting polymer with an extended pi-pi* conjugated electron system, was used as a sensitizer/protector covering the V-doped Ta3N5 particles to enhance the charge transfer efficiency for migration of the photogenerated electrons and holes to the photocatalyst surface. The PANI cover also prevented Ta3N5 from oxidizing the generated holes (self photocorrosion). As a result, the synthesized V-Ta3N5/PANI material exhibited very high photocatalytic activity for water splitting, producing H-2 and O-2 even under visible light. The production rates of H-2 and O-2 generated from water splitting by V-Ta3N5/PANI were 745 and 370 (mu mol g(-1) cat h(-1)), respectively. (C) 2017 Elsevier Inc. All rights reserved.