We grow Fe3O4 and TiO2 nanoparticles (NPs) on Au(111), YSZ(111) and Al2O3(0001) substrates to investigate the structure, shape, defects and chemical composition of the NPs using surface sensitive X-ray diffraction, scanning probe microscopy, X-ray photoelectron spectroscopy and infrared reflection absorption spectroscopy techniques at the DESY NanoLab in the Center for X-ray and Nano Science CXNS, DESY in strong collaboration with A1 and A6.
Furthermore, we aim to understand the interaction of long chain organic acids with Fe3O4 and TiO2 nanostructures, the results can be directly used to understand the interaction of the ligand stabilized NPs in collaboration with projects A1, A4, A6 and A8. The ligand/NPs/oxide system will be characterized using spectroscopic methods, such as polarization-dependent FT-IRRAS, to study adsorption geometries and sites; X-ray photoemission spectroscopy to determine binding energies and adsorbate configuration; and the surface sensitive X-ray diffraction for the adsorbate-induced structural and shape changes of the NPs.
Thermal stability of Fe3O4 and TiO2 is the other focus of this project to gain insight into the structural and chemical changes of the NPs under the synthesis conditions, such as changes in shape, size, facet dis-tribution and oxidation state. The heat treatment under ambient condition (Ar/O2) will be additionally studied in close collaboration with projects A1, A4, A5 and A6.
Finally, we study the wet-chemically prepared layers of NPs from A1 with x-ray reflectometry in order to determine the density profiles of the NPs, in particular with high-energy x-ray diffraction at buried interface structures. An in-situ investigation of these interfaces under mechanical load is planned in collaboration with A6.
Prof. Dr. rer. nat. Andreas
|Dr. rer. nat. Heshmat Noei|
surface spectroscopy (XPS, FTIR)
probe microscopy (AFM, STM, SEM)
metal oxide surfaces nanoparticles
2. S. Tober, et al.: Observation of iron diffusion in the near-surface region of magnetite at 470K. Physical Review Re-search 2, 023406 (2020)
... and more on the list of publications.