Visible-Light Photocatalytic Degradation of BiTaO₄ Photocatalyst and Mechanism of Photocorrosion Suppression

BiTaO4 photocatalyst for methylene blue (MB) degradation, which worked under visible-light irradiation, was systematically investigated for the first time. BiTaO4 possess similar degradation ability of TiO2−XNX under visible-light irradiation (λ > 420 nm). Density functional calculations revealed that Bi 6s orbitals contributed to the formation of valence band, resulting in narrowing the band gap. Moreover, comparing with BiNbO4, we found BiTaO4 showed photocorrosion suppression performance during the photocatalytic process. The differences in the photocorrosion suppression between BiTaO4 and BiNbO4 could be attributed to the conduction curvature and bandwidth, leading to differences in the mobility of photogenerated electrons formed in the conduction bands, which mainly consisted of Ta 5d and Nb 4d orbitals, respectively.