ABSTRACT
Since the first report of Fujishima et al. on the UV-light induced redox chemistry over titanium dioxide (TiO2), photocatalysis has received remarkable interest as a green and sustainable technology for energy and environmental issues [7-10]. The photocatalytic oxidation process combines oxygen, water, and VOCs on the catalyst surface to produce CO2 and H2O under UV irradiation (Fig. 11.1). Activation of TiO2 is achieved through the absorption of a photon (hv) from UV irradiation source. This results in the promotion of an electron (e-) from the valence band to the conduction band, with the generation of highly reactive positive holes (h+) in the valence band. This can
cause aggressive oxidation of the surface-adsorbed VOC molecules and converts them into CO2 and water. In the photocatalytic process of formaldehyde, formic acid was found on the TiO2 surface as the partial oxidation byproduct [11].
