Photocatalytic activity of single and mixed nanosheet-like Bi2WO6 and TiO2 for Rhodamine B degradation under sunlike and visible illumination

The photocatalytic activity, under sunlike illumination, for Rhodamine B (RhB) degradation using Bi2WO6-TiO2 samples, is reported. Two different kinds of Bi2WO6-TiO2 samples were studied, obtained by distinct methods: first, a mechanical mixing, by adding to synthesized nanosheet-like Bi2WO6 powder the corresponding amount of TiO2 nanoparticles (P25) in order to obtain physical mixtures of both catalysts with different percentages of TiO2 (5, 10 and 50 wt%); second, a single Bi2WO6-TiO2 heterostructure was prepared by adding commercial TiO2-P25 to the Bi2WO6 precursors (50 wt%) prior to the hydrothermal treatment, thus obtaining a sample with in situ TiO2 incorporation. Comparisons between the photocatalytic behaviour of these samples and those exhibited by the single materials Bi2WO6 and TiO2 (P25) were carried out, in order to establish the effect not only of the TiO2 addition but also of the way in which TiO2 (P25) is incorporated. The role of each single photocatalyst in the mixtures in the RhB degradation and mineralization under sunlike and just visible illumination was also studied. (C) 2012 Elsevier B.V. All rights reserved.