Effect of the carbon coating in Fe–C–TiO2 photocatalyst on phenol decomposition under UV irradiation via photo-Fenton process

Fe–C–TiO2 photocatalysts which contained the residue carbon (0.2–3.3 mass%) were prepared from a mixture of TiO2 and FeC2O4 through the heating at 673–1173 K in Ar. These photocatalysts did not show a high adsorption of phenol, but they were active in photo-Fenton reactions during decomposition of phenol under UV irradiation with addition of H2O2. It was proved that Fe2+ governed the photoactivity of Fe–C–TiO2 photocatalysts, it decreased with heat-treatment temperature above 773 K. For comparison, Fe–TiO2 photocatalyst was prepared by heating TiO2 and FeC2O4 at 823 K in air for 3 h. Phenol decomposition was going much slower on Fe–TiO2 photocatalyst in comparison with Fe–C–TiO2, of which mechanism was different, on the former phenol was decomposed by the radical reaction, on the latter through a complex reaction with iron and intermediates of phenol decomposition. Therefore carbon-coating TiO2 was found to be advantageous for mounting iron and its application for the phenol decomposition via photo-Fenton process.