Structural and photocatalytic properties of the new solid photocatalyst In₂BiTaO₇

In₂BiTaO₇ was synthesized using the solid-state reaction method and its photocatalytic properties were investigated. The results of powder X-ray diffraction (XRD) indicated that the compound crystallizes in the pyrochlore-type structure, cubic system with space group Fd-3m. The lattice parameter is 10.6972(1) Å. In addition, the compound shows strong optical absorption in the visible region (λ > 420 nm) and the band gap of In₂BiTaO₇ was estimated to be about 2.47 eV. For the photocatalytic reaction, H₂ or O₂ evolution was observed from CH₃OH/H₂O or AgNO₃ solution respectively with In₂BiTaO₇ as the photocatalyst under visible light irradiation, indicating that In₂BiTaO₇ is responsive to visible light for splitting water. Furthermore, the catalyst remained photoactive in the wavelength range up to 510 nm. Photocatalytic degradation of methylene blue (MB) dye over the compound was further investigated under visible light irradiation. The results showed that complete removal of aqueous MB could be achieved after irradiation for 135 min over In₂BiTaO₇. Furthermore, under visible light irradiation In₂BiTaO₇ showed markedly higher catalytic activity compared to P-25 for MB photocatalytic degradation.