A superior visible light-driven photocatalyst: Europium-doped bismuth tungstate hierarchical microspheres

摘要

Novel visible light-driven photocatalyst europium-doped bismuth tungstate (Eu/Bi_2WO_6) hierarchical microspheres has been synthesized by a hydrothermal route. The obtained products were characterized by SEM, EDX, XRD, XPS and DRS technologies. Their photocatalytic activities were determined by oxidative decomposition of Rhodamine-B (RhB) in aqueous solution under visible light irradiation. The results revealed that the europium doping greatly improved the photocatalytic efficiency of Bi_2WO_6 microspheres. The photodegradation reactions of RhB by Eu/Bi_2WO_6 composites followed the first-order kinetics. The possible reasons for Eu/Bi_2WO_6 composites showing higher activity than pure Bi_2WO_6 are mainly ascribed to the enhanced absorption in the visible region and the suppressed recombination between photogenerated electrons and holes in composite samples.