Sintesis y caracterización de sólidos co-modificados de titania empleados en la degradación fotocatalítica de fenol

Phenol was used as probe molecule for the photo-activity evaluation of reduced and iron doped anatase (TiO₂). The iron catalyst was prepared by wet impregnation of anatase with Fe(NO₃)₃ and a subsequent calcination at 500°C. In other hand, reduced TiO₂ was obtained by HNO₃ pre-treatment and reduction under hydrogen flow at 500°C. Co-modified catalysts were synthetized by three procedures: 1) mechanical mixture of solids, 2) impregnation of the iron salt to the reduced TiO₂ and, 3) reducing the iron doped anatase. The photocatalysts were characterized by FT-IR, Mössbauer spectroscopy, XRD and UV-Vis absorption of aqueous dispersion. It was found that iron do not change crystalline structure of TiO₂, although the UV-Vis absorption showed a little batochromic shift. Phenol degradation was 1.8 times higher than pure anatase. The reductive treatment, provoke certain chemical surface changes beneficial to the TiO₂ activity, making TiO₂ 1.6 times more active. The co-modified solid synthesized by mechanical mixture reached an activity three-fold higher than the original semiconductor, being this co-modification method the most advantageous, suggesting also an electron transfer mechanism between semiconductors.