Bulk and surface analysis of Ti _{1– <i>x</i>} Fe <i> _x </i> O ₂ /Fe ₂ O ₃ composites prepared by solid state reaction for photocatalytic applications

Abstract

Ti 1– x Fe x O 2 / Fe 2 O 3 ( x = 0.3, 0.6, and 0.7 wt%) composites were prepared by solid state reaction of the oxides TiO 2 (rutile phase) and Fe 2 O 3 at 550 °C. The following techniques were applied for the characterization of the composites: X‐ray powder diffraction, Mössbauer spectroscopy, SEM, energy dispersive X‐ray spectroscopy and adsorption of nitrogen. The anatase/rutile/hematite ratio and the abundance of Fe 3+ were quantified. The results indicate that Fe 3+ substituted Ti 4+ in the rutile structure and that the α‐Fe 2 O 3 phase was predominantly on the surface of the crystalline Ti 1– x Fe x O 2 powders. A substantial increase of the materials density, with respect to rutile, favoured the application of the composites in photocatalytic experiments. The performance of the solids upon the photodegradation of aqueous solutions of carbofuran was evaluated. The Lewis sites created in the composites correlated directly with the photodegradation rate constant of carbofuran and the decrease of the total organic carbon content in the treated solutions. Copyright © 2011 John Wiley &amp; Sons, Ltd.