WO3 nanoparticles decorated on both sidewalls of highly porous TiO2 nanotubes to improve UV and visible-light photocatalysis

The hybrid structure of nanoparticle-decorated nanotubes has the advantage of both large specific surface areas of nanoparticles and anisotropic properties of nanotubes, which is desirable for many applications. In this study, WO3 nanoparticles decorated on highly porous TiO2 nanotubes along both internal and external sidewalls (WO3@TiO2@WO3 heterostructures) were synthesized through emulsion electrospinning, thermal evaporation, and thermal annealing. The WO3@TiO2@WO3 heterostructures had large specific surface areas, high porous structure and excellent interface (between WO3 nanoparticles and TiO2 nanotubes). Three other samples, TiO2 nanofibers, TiO2 nanotubes, and TiO2 nanofibers decorated by WO3 nanoparticles, were prepared in order to compare with the WO3@TiO2@WO3 heterostructures for photocatalysis with both UV and visible light irradiation. The new material (WO3@TiO2@WO3 heterostructures) had a wide range of light absorption and demonstrated the best photocatalytic performance. The possible growth mechanism and reasons for high photocatalysis are discussed in detail.