The Structural, Photocatalytic Property Characterization and Enhanced Photocatalytic Activities of Novel Photocatalysts Bi(2)GaSbO(7) and Bi(2)InSbO(7) during Visible Light Irradiation

In order to develop original and efficient visible light response photocatalysts for degrading organic pollutants in wastewater, new photocatalysts Bi(2)GaSbO(7) and Bi(2)InSbO(7) were firstly synthesized by a solid-state reaction method and their chemical, physical and structural properties were characterized. Bi(2)GaSbO(7) and Bi(2)InSbO(7) were crystallized with a pyrochlore-type structure and the lattice parameter of Bi(2)GaSbO(7) or Bi(2)InSbO(7) was 10.356497 Å or 10.666031 Å. The band gap of Bi(2)GaSbO(7) or Bi(2)InSbO(7) was estimated to be 2.59 eV or 2.54 eV. Compared with nitrogen doped TiO(2), Bi(2)GaSbO(7) and Bi(2)InSbO(7), both showed excellent photocatalytic activities for degrading methylene blue during visible light irradiation due to their narrower band gaps and higher crystallization perfection. Bi(2)GaSbO(7) showed higher catalytic activity compared with Bi(2)InSbO(7). The photocatalytic degradation of methylene blue followed by the first-order reaction kinetics and the first-order rate constant was 0.01470 min(−1), 0.00967 min(−1) or 0.00259 min(−1) with Bi(2)GaSbO(7), Bi(2)InSbO(7) or nitrogen doped TiO(2) as a catalyst. The evolution of CO(2) and the removal of total organic carbon were successfully measured and these results indicated continuous mineralization of methylene blue during the photocatalytic process. The possible degradation scheme and pathway of methylene blue was also analyzed. Bi(2)GaSbO(7) and Bi(2)InSbO(7) photocatalysts both had great potential to purify textile industry wastewater.