Photocatalytic hydrogen evolution on P-type tetragonal zircon BiVO4.

• P-type tetragonal zircon BiVO 4 (P-BiVO 4) film was grown on FTO glass via hydrothermal method. • Interstitial oxygen is the main cause of p-type conductivity. • The P-BiVO 4 exhibit photocatalytic hydrogen production activity even its conduction band level is not negative enough. • The downward band-bending and the hot-electrons lead to the H 2 reduction. Tetragonal zircon BiVO 4 (P-BiVO 4) were grown on fluorine-doped tin oxide (FTO) glass via hydrothermal method. The cathodic photocurrent and Mott-Schottky analysis indicate that the tetragonal zircon BiVO 4 is a p-type semiconductor. Inductively coupled plasma (ICP) analysis and X-ray photoelectron spectrum showed that there are Bi vacancies and interstitial oxygen exist in the crystal, which are the origin of the p-type conductivity. The flat band potential of the P-BiVO 4 is about 1.33 V (vs Ag/AgCl) inferred from Mott-Schottky plots. Combining with diffuse reflection spectrum and valence band X-ray photoelectron spectrum, the calculated conduction band value of the P-BiVO 4 is about 0.06 V vs RHE, slightly higher than the reduction potential of hydrogen. However, the P-BiVO 4 exhibit hydrogen production activity under Xe light irradiation even though its conduction band level is not negative enough. This can be attributed to the hot carrier processes in p-type semiconductors. [ABSTRACT FROM AUTHOR]