Activation Energy for Dibenzofuran Desorption from Fe 3+ /TiO 2 and Ce 3+ /TiO 2 Photocatalysts Coated onto Glass Fibres

Abstract

In this work, TiO₂, Fe³⁺/TiO₂ and Ce³⁺/TiO₂ photocatalytic films were respectively immobilized on glass fibres via the sol—gel technique to prepare supported photocatalysts. Temperature programmed desorption (TPD) experiments were conducted to measure the TPD curves for the removal of dibenzofuran from these photocatalysts, from which the activation energy for dibenzofuran desorption from the photocatalyst surfaces was estimated.

The results showed that the activation energies for dibenzofuran desorption from the photocatalysts TiO₂, Ce³⁺/TiO₂ and Fe³⁺/TiO₂ coated separately onto the glass fibres were 16.41 kJ/mol, 22.55 kJ/mol and 33.59 kJ/mol, respectively, while the hardness values of the ions Fe³⁺, Ce³⁺ and Ti⁴⁺ were respectively 13.1 eV, 11.9 eV and 10.6 eV.

The data indicated that the use of Fe³⁺ or Ce³⁺ ions for doping a TiO₂ photo-catalyst increased the local hardness of the doped TiO₂ photocatalyst surface. This, in turn, increased the activation energy for the desorption of dibenzofuran from such a TiO₂ photocatalyst surface.