Elaboration, charge-carrier lifetimes and activity of Pd-TiO2 photocatalysts obtained by gamma radiolysis

The surface of four commercial TiO2 compounds (Cristal Global PC-series) has been modified by Pd nanoparticles induced by gamma radiolysis. Their photocatalytic properties have been followed by phenol and rhodamine B photocatalytic degradation in aqueous suspensions under UV and visible light. Their electronic properties have been studied by time resolved microwave conductivity (TRMC) method to follow the charge-carrier dynamics. The experiments evidence a complex behavior of the surface-Pd. Its influence depends on the pollutant and on the irradiation. The modification may be strongly favorable to the photocatalytic activity. The results have been interpreted in terms of modification of charge-carrier dynamics with TRMC measurements. The surface-Pd plays a role in charge-carrier separations, increasing the photocatalytic activity under UV-light, but shows no effect on the absorption properties, preventing the creation of an activity under visible light. (C) 2012 Elsevier B.V. All rights reserved.