Phase transition and lattice expansion during hydrogen loading of nanometer sized palladium clusters

Mohammed Suleiman Shtaya's picture
Journal Title, Volume, Page: 
Journal of Alloys and Compounds 356:644-648
Year of Publication: 
2003
Authors: 
Mohammed Suleiman
Institute of Material Physics, University of Göttingen, 37077 Göttingen, Germany
Current Affiliation: 
Department of Chemistry, An-Najah National University
Preferred Abstract (Original): 
In situ X-ray diffraction ( XRD) measurements for Pd-clusters (3.8 and 6.0 nm) are performed during hydrogen loading and unloading.
The lattice parameter increases as a function of the hydrogen partial pressure. The expansion is smaller than that of bulk palladium and is
shown to be cluster-size dependent. An (a–a9) phase transition was observed for the large clusters but small clusters do not show this
transition. XRD analysis of the as-prepared clusters show that the 3.8-nm sized clusters predominantly have an icosahedral structure,
while the 6.0-nm sized clusters have a cubic structure. The effect of size and structure of the cluster on the lattice expansion and on the
phase transition will be discussed.
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