Berlin 2005 – wissenschaftliches Programm
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M: Metallphysik
M 19: Nanoskalige Materialien II
M 19.4: Vortrag
Samstag, 5. März 2005, 11:45–12:00, TU H111
selective synthesis of nano-meter-sized clusters: size and structure determination — •M. Suleiman1, C. Borchers1, M. Guerdane1, N. M. Jisrawi2, M. T. Reetz3, R. Kirchheim1, H. Teichler1, and A. Pundt1 — 1Institute fuer Materialphysik, Uni. Goettingen — 2Department of Physics, Birzeit University, Palestine — 3Max-Planck-Institut fuer Kohlenforschung, Muelheim
Using electrochemical technique [[1]] we will show that not only the clusters size can be selectively prepared but also the structure. Palladium clusters are prepared in a simple two-electrode cell in which surfactant is used as electrolyte and stabiliser. The obtained cluster sizes depend on the preparation parameters, such as: current density, temperature, type of solvent and distance between the electrodes. Using XRD and TEM analysis show a narrow size distribution ((± 0.5 nm)). The cluster size is evaluated from the XRD data and TEM images. It will be shown that a Fourier transform of the XRD pattern gives a fairly accurate value of the cluster size. XRD and HREM analysis revealed that the structure of the Pd clusters is size dependent. The critical size for the structural transition from icosahedral to cubic structure was found to be 4.8 nm. This result is in good agreement with the critical size value obtained from MD-simulation for a model Pd clusters [[2]]. First results on preparing Ni, Co and core shell clusters using this electrochemical technique will be presented.
This work is supported by the DFG via SFB 602 [[1]] M. T. Reetz, W. Helbig, J. Am. Chem. Soc., 11 ((1994)) 7401 [[2]] N. M. Jisrawi, A. Pundt, M. Guerdane, H. Teichler accepted in Acta Mater.