Novel photocatalytic activity of vanadium-doped tantalum nitride sensitized/protected by polyaniline for efficient visible light water splitting

- V dopant and PANI sensitizer synergistically enhanced the photocatalytic activity of Ta3N5.
- V dopant enhanced e−/h+ separation and prolonged the lifetime of the generated e− and h+.
- PANI sensitizer covering Ta3N5 enhanced the charge transfer efficiency of the photocatalyst.
- PANI cover protected Ta3N5 from self photocorrosion (oxidation of generated holes).
- V-Ta3N5/PANI greatly improved overall water splitting efficiency for production of H2.

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 π-π∗ 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 H2 and O2 even under visible light. The production rates of H2 and O2 generated from water splitting by V-Ta3N5/PANI were 745 and 370 (µmol g−1cat h−1), respectively.

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