Superior photocatalytic performance by vertically aligned core-shell TiO2/WO3 nanorod arrays

Using two consecutive regarding glancing angle depositions at different deposition angles and with different materials, a WO3-core TiO2-shell nanostructure has been fabricated and has photocatalytic enhancement up to 70 times over amorphous single layer TiO2 thin films, 13 times enhancement over crystalline (anatase) TiO2 thin films, and 3 times enhancement over c-TiO2/a-WO3 two-layer thin films, with much less the load of TiO2. We believe that the mechanism for the photocatalytic enhancement is from the increased density of charge separated electron-hole pairs aided by the WO3 layer, the interfacial area between the two-layers, and the large surface area from the porous nanostructure. (C) 2009 Elsevier B.V. All rights reserved.