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

Novel visible light-driven photocatalyst europium-doped bismuth tungstate (Eu/Bi2WO6) 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 Bi2WO6 microspheres. The photodegradation reactions of RhB by Eu/Bi2WO6 composites followed the first-order kinetics. The possible reasons for Eu/Bi2WO6 composites showing higher activity than pure Bi2WO6 are mainly ascribed to the enhanced absorption in the visible region and the suppressed recombination between photogenerated electrons and holes in composite samples. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.