Photophysical Property and Photocatalytic Activity of New Gd(2)InSbO(7) and Gd(2)FeSbO(7) Compounds under Visible Light Irradiation

Gd(2)InSbO(7) and Gd(2)FeSbO(7) were synthesized first, and their structural and photocatalytic properties were studied. The lattice parameters and the band gaps for Gd(2)InSbO(7) and Gd(2)FeSbO(7) were 10.449546 Å, 10.276026 Å, 2.897 eV and 2.151 eV. The photocatalytic degradation of rhodamine B was performed with Gd(2)InSbO(7) and Gd(2)FeSbO(7) under visible light irradiation. Gd(2)InSbO(7) and Gd(2)FeSbO(7) had higher catalytic activity compared with Bi(2)InTaO(7). Gd(2)FeSbO(7) exhibited higher catalytic activity than Gd(2)InSbO(7). The photocatalytic degradation of rhodamine B followed with the first-order reaction kinetics, and the first-order rate constant k was 0.01606, 0.02220 or 0.00329 min(−1) with Gd(2)InSbO(7), Gd(2)FeSbO(7) or Bi(2)InTaO(7) as photocatalyst. Complete removal of rhodamine B was observed after visible light irradiation for 225 min or 260 min with Gd(2)FeSbO(7) or Gd(2)InSbO(7) as photocatalyst. The evolution of CO(2) was realized, and it indicated continuous mineralization of rhodamine B during the photocatalytic process. The possible photocatalytic degradation pathway of rhodamine B was proposed.