Figure 1.

Efficiency enhancement mechanisms for photocatalysis using CNT–TiO₂ nanocomposites. (a) CNT scavenges electrons generated in TiO₂, resulting in excessive holes on the surface for redox actions. (b) CNT acts as a photosensitizer and injects electrons and holes into TiO₂ for redox actions. (c) CNT introduces energy states in the band gap of TiO₂ which can convert long wavelength photons to electrons and holes. Adapted from [18]. Copyright (2009) WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.