Photophysical Property and Photocatalytic Activity of New Gd₂InSbO₇ and Gd₂FeSbO₇ Compounds under Visible Light Irradiation

Abstract: Gd₂InSbO₇ and Gd₂FeSbO₇ were synthesized first, and their structural and photocatalytic properties were studied. The lattice parameters and the band gaps for Gd₂InSbO₇ and Gd₂FeSbO₇ were 10.449546 Å, 10.276026 Å, 2.897 eV and 2.151 eV. The photocatalytic degradation of rhodamine B was performed with Gd₂InSbO₇ and Gd₂FeSbO₇ under visible light irradiation. Gd₂InSbO₇ and Gd₂FeSbO₇ had higher catalytic activity compared with Bi₂InTaO₇. Gd₂FeSbO₇ exhibited higher catalytic activity than Gd₂InSbO₇. 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 Gd₂InSbO₇, Gd₂FeSbO₇ or Bi₂InTaO₇ as photocatalyst. Complete removal of rhodamine B was observed after visible light irradiation for 225 min or 260 min with Gd₂FeSbO₇ or Gd₂InSbO₇ as photocatalyst. The evolution of CO₂ was realized, and it indicated continuous mineralization of rhodamine B during the photocatalytic process. The possible photocatalytic degradation pathway of rhodamine B was proposed.