Chair for Multicomponent Materials

Nanoscale mixed metal oxides as photocatalysts

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.