The coupling of TiO₂ with other metal oxide semiconductors (ZnO, SnO₂ , and CeO₂ ) improves the photocatalytic efficiency of TiO₂ via enhancing the charge separations and broadening the absorption of the solar spectrum. Among various mixed oxides, CeO₂ –TiO₂ combination attracts the attention for catalytic applications due to its novel physicochemical and electronic properties, which are totally different from their individual components. These catalytic and optical properties are due to fluctuating oxidation states between Ce³⁺ and Ce⁴⁺.

Fig 1. (a) Photocatalytic degradation of MB and (b) optical image of MB coated CeO₂–TiO₂ deposited quartz glass before and after 5 min UV irradiation and (c) Inside Back Cover Illustration for “Cauliflower-like CeO₂ –TiO₂ hybrid nanostructures with extreme photocatalytic and self-cleaning properties.”

Recently we have shown that magnetron sputtering and gas aggregation source (GAS) approaches were combined for the preparation of columnar TiO₂ structures decorated with PdO nanoparticles (NPs). The solvent-free synthesis approach provides good control of surface coverage, size, morphology, and stoichiometry of PdO NPs in comparison to wet chemical synthesis methods. Possibly the steady equilibrium between the formation of PdO and PdO₂ under UV irradiation seemed to foster the charge separation efficiency, and this enhanced the photocatalytic performance.

Fig 2. (a) Dynamic switching mechanism and (b) direct electron transfer mechanism for PdO-TiO₂ photocatalyst under UV illumination.

Selected publications

S. Veziroglu, K. Röder, O. Gronenberg, A. Vahl, O. Polonskyi, T. Strunskus, H.-G. Rubahn, L. Kienle, J. Adam, J. Fiutowski, F. Faupel, O.C. Aktas, Cauliflower-like CeO₂ –TiO₂ hybrid nanostructures with extreme photocatalytic and self-cleaning properties, Nanoscale. 11 (2019) 9840–9844.

S. Veziroglu, J. Hwang, J. Drewes, I. Barg, J. Shondo, T. Strunskus, O. Polonskyi, F. Faupel, O.C. Aktas, PdO nanoparticles decorated TiO₂ film with enhanced photocatalytic and self-cleaning properties, Mater. Today Chem. 16 (2020) 100251.