Degradation of Acetaldehyde with Doped TiO2 Photocatalyst Under Visible Light Irradiation

C-, V-doped TiO2 photocatalysts are prepared by a sol-gel process. These catalysts are highly active for the degradation of acetaldehyde both under visible irradiation (> 420 nm) and in the dark, especially for 2.0% V-containing co-doped TiO2. Characterization results suggest that vanadium ions are introduced both on the surface and into the bulk of TiO2. A free electron, induced by the formation of V 5+ in the sublayers of TiO2, is delocalized and promoted into the conduction band by thermal energy and further transferred to O2, generating superoxide radical anion (O2 •) that is responsible for degradation of acetaldehyde in the dark. The doped elemental carbon increases the visible light sensitivity, the surface area, and the dispersion of vanadium.