ceria-titania nanostructures for photocatalytic applications

Abstract

TiO2 is the most active and most suitable semiconductor photocatalyst. It is non-toxic, available, chemical and thermically stable but it has some disadvantages such as wide band gap (UV required) and fast recombination of charge carriers. CeO2 is one of the most reported rare earth metal oxides used in catalysis, based on its enhanced structural and redox properties. It is an effective coupling material with TiO2 in the field of visible light driven photocatalysis. The band gap of TiO2 is 3.2 eV, so it absorbs light in the UV region. The ceria addition induces a decrease in the energy gap and enhances the adsorption in the visible region, enabling the use of the catalyst under solar light. The aim of this thesis is to optimize the synthetic procedure in order to obtain nano octahedra of pure TiO2 and Ce-doped TiO2 and to study the effect of Ce loading on the morphology of titania nanoparticles and their photocatalytic activity. The TiO2 samples containing different CeO2 loadings (ranging from 0 to 1.5 wt.%) were prepare by an ultrasonication-hydrothermal reaction of potassium titanate nanowires precursor. Also the Potassium titanate nanowires (TNWs) were prepared by hydrothermal reaction. All the materials were characterize by different techniques: XPS,XRD,HRTEM,DRIFT UV-VIS. The photocatalytic tests were carried out in aqueous solution at r.t. and P atm, under UV, visible and under simulated solar light irradiation with different target pollutant molecules.