Photo-Electrochemical Studies on TiO 2 -Doped Ce (III/IV) Oxides Nanoparticles in Aqueous Electrolytes

Abstract

Photoelectrochemical studies on TiO2 doped with Ce2O3 or CeO2 took place in aqueous solutions of [Fe(CN)6]4- as the source of hydrated electrons. Our studies show that doping TiO2 with CeO2 gave better photocatalytic reduction of [Fe(CN)6]3- than TiO2 doped with Ce2O3. However the TiO2 assemblies doped with either Ce(III) or Ce(IV) oxides give less photochemical reduction of [Fe(CN)6]3- that the oxides of pure metals (Ti or Ce). In both cases a lowering of the band gaps of TiO2 was noticed. Immobilized TiO2 doped with Ce oxides on a FTO (Fluorine Ten Oxide) surface gave greater photocurrent with I2/I3– than that recorded for [Fe(CN)6]3-/4- redox systems. Our studies indicate that the TiO2 doped with Ce2O3 or CeO2 maintained photoactivity after being immobilized in thin solid sheets and can be used in all solid state photoelectron-chemical cells.