• Abstract talk
  • MS7.005

Investigation of the morphology of TiO2-CeO2 mixed-oxide nanoparticles for photocatalytic applications


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spectrum A


Ceramics and composites


  • MS 1: Energy-related materials and catalysts
  • MS 7: Ceramics and composites


Marie Elis (Kiel / DE), Marius Kamp (Kiel / DE), Martin Hicke (Kiel / DE), Jonas Drewes (Kiel / DE), Cenk Aktas (Kiel / DE), Franz Faupel (Kiel / DE), Salih Veziroglu (Kiel / DE), Lorenz Kienle (Kiel / DE)


Abstract text (incl. figure legends and references)


Titanium(IV)oxide (TiO2) nanoparticles are of high interest for a broad variety of applications, e.g. (photo)catalysis, self-cleaning and sensing. The photocatalytic performance of TiO2 can be improved by controlling its crystal structure [1] as well as by the addition of noble metals [2] or oxides [3]. Combination of TiO2 and other oxide especially with CeO2 is one of the promising ways for effective electron-hole separation due to easy fluctuation of oxidation states of Ce [3].


The presented research aims to find connections between the real structure of TiO2-CeO2 particles (i.e. crystal structure, morphology and composition) and their photocatalytic properties. Understanding these connections, allows to purposefully adapt the particles to the respective application and optimize their performance.

Materials & Methods

A custom-made gas aggregation cluster source (GAS) was used to synthesize mixed-oxide nanoparticles. Ti and Ce were sputtered from a custom build Ti-Ce target, agglomerated under admixture of O2 as reactive gas and were deposited on Si wafer pieces. After deposition, the particles were heat treated at 700 °C under ambient conditions.

For TEM preparation the particles were scratched off the substrate and transferred to a Cu lacey TEM grid (Plano GmbH).

The particles were analyzed in a Jeol NeoArm JEM-ARM200F STEM equipped with two windowless EDX detectors. STEM-HAADF imaging in combination with EDX spectroscopy provides information on the particle morphology and the distribution of Ti and Ce. HRTEM as well as HRSTEM-HAADF images can reveal the nature of the interfaces between TiO2 and CeO2 crystals.


First measurements on TiO2-CeO2 nanoparticles with a high concentration of Ce have shown demixing of a Ti-rich and a Ce-rich phases. Separate Ti-rich and Ce-rich particles have been observed as well as a core-shell type particle with a Ti-rich core covered by a Ce-rich shell. Ce-rich as well as Ti-rich phases where found to be crystalline. The crystal phase of CeO2 was determined to be Fm-3m by electron diffraction. Due to the low Ti concentration, the crystal phase of TiO2 was not determined by electron diffraction. Instead, the phase of TiO2 was observed to be brookite phase in FFTs of HRTEM images. The investigation of further samples with different Ti/Ce-ratios synthesized at different process parameters are expected to show a broader variation in particle morphology and give an insight into the dependence of the particle morphology on Ti/Ce-ratio as well as GAS process parameters.


At high Ce concentration, demixing into different morphologies with a Ce-rich and a Ti-rich phase can be observed in the mixed-oxide nanoparticles. Both phases are crystalline. To achieve anatase phase, which is desirable for high photocatalytic activity, the GAS process parameters need to be adjusted. Earlier studies with pure TiO2 particles have shown that the crystal phase can be varied by changing the magnetron voltage.

For further investigations, the magnetron voltage window for the synthesis of anatase phase TiO2 in the mixed-oxide system will be investigated. In addition, the Ti/Ce ratio will be varied to study the influence of the particle composition on the morphology.


[1] A. Sclafani, J. M. Herrmann, J. Phys. Chem., 1996, 100, 13655–13661

[2] S. Veziroglu et al., ACS Appl. Mater. Interfaces, 2020, 12, 14983–14992

[3] S. Veziroglu et al., Nanoscale, 2019, 11, 9840-9844

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