Photocatalytic decomposition of perfluorooctanoic acid by iron and niobium co-doped titanium dioxide

The photocatalytic decomposition of perfluorooctanoic acid (PFOA) in aqueous solution using Fe and Nb co-doped TiO 2 (Fe:Nb-TiO 2) prepared by sol–gel method was investigated. The photocatalytic activity of Fe:Nb-TiO 2 towards PFOA degradation was compared to that of pure TiO 2 synthesized using the same method, and that of the commercially available TiO 2 photocatalyst, Aeroxide TiO 2 P25 (AO-TiO 2 P25). The photocatalysts were characterized by XRD, DRS, BET-N 2 adsorption isotherm, and SEM-EDX techniques and the data were correlated to the photocatalytic activity. Fe:Nb-TiO 2 showed the highest activity compared to the undoped TiO 2 and the commercially available TiO 2. Such activity was attributable to the effects of co-doping both on the physico-chemical properties and surface interfacial charge transfer mechanisms. Perfluorocarboxylic acids (PFCAs) with shorter carbon chain length and fluoride ions were identified as photocatalytic reaction intermediates and products.