Solar light assisted photodegradation of phenol with hydrogen peroxide over iron-doped titania catalysts: Role of iron leached/readsorbed species

Nanostructured iron-doped TiO2 catalysts with anatase structure and two different iron contents (0.7 and 3.5 wt.%) have been prepared by a combined sol–gel/microemulsion method and examined with respect to their behaviour for photocatalytic degradation of aqueous phenol with H2O2 under solar light. The activity results are compared with those obtained for similarly prepared undoped systems as well as Degussa P25 reference catalyst and have been complemented with structural/morphological and electronic characterization analyses achieved by XRD, TEM, Raman, SBET, UV–vis DRS and XPS techniques. In contrast to typically observed results, the highest photoactivity is obtained for the catalyst with highest iron loading while that with 0.7% Fe displays lower photoactivity than undoped samples. Such unusual behaviour has been attributed to the contribution of new photoactive iron complexes generated on the surface of the catalyst as a consequence of iron leaching and readsorption processes taking place during the course of phenol photodegradation process.

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► Unusually high phenol solar photodegradation activity is observed over iron-doped catalyst with high iron loading.
► Iron leaching/readsorption observed during the reaction indicates a mechanism of surface iron complexes.
► Iron becomes fully readsorbed on the catalyst surface during the course of the reaction, thus facilitating products separation.