Three-dimensional TiO2/Bi2WO6 hierarchical heterostructure with enhanced visible photocatalytic activity

A three-dimensional TiO₂/Bi₂WO₆ hierarchical heterostructure was successfully prepared by a simple and practical liquid phase method. The as-synthesised nanostructure consisted of TiO₂ nanoparticles growing on the surface of flower-like Bi₂WO₆ microspheres. The UV-vis diffuse reflectance spectra indicated that the TiO₂/Bi₂WO₆ composites have a significantly enhanced optical absorption in the visible light region and red-shift phenomenon compared with that of pure Bi₂WO₆ microspheres. The photocatalytic activity of the TiO₂/Bi₂WO₆ composites increases first and then decreases with increasing loading content of TiO₂ under 500 W Xe lamp light irradiation. The composite coated with 3 ml content tetrabutyl titanate showed the highest photocatalytic activity compared with that of the other samples in the decomposition of Rhodamine B in water which is a typical model pollutant. The improved light harvesting ability and efficient separation of photo-generated electron and hole pairs could be responsible for the improved photocatalytic performance.