Regensburg 2004 – wissenschaftliches Programm
M 3.1: Vortrag
Montag, 8. März 2004, 10:15–10:30, H4
Pd-H clusters: Like and faraway from bulk-like behaviour — •M. Suleiman1, N. M. Jisrawi2, C. Borchers1, C. Bähtz3, D. Marcano1, R. Kirchheim1, and A. Pundt1 — 1Institut für Materialphysik, Tammannstr. 1, D-37077 Göttingen — 2Dept. of Physics, Berzeit university POB 14, Berzeit, Palestine — 3Darmstadt University of Technology, Institute of Material Science, 64287 Darmstadt
The thermodynamic and the kinetic absorption behaviour of the Hydrogen in nanometer-sized Palladium clusters will be discussed. Pressure-concentration isotherms (P-x-T) obtained from gravimetric measurements will be presented. The absorption isotherms resemble those for bulk palladium above the critical temperature showing a sloped plateau. However, adsorbtion isotherms show the existence of a hysteresis even in the smallest (3.0 nm ) clusters indicating a phase transition. Structural information obtained by in-situ XRD measurements during Hydrogen loading will be presented. The large Pd clusters show the (α-β) phase transition common for bulk Pd, whereas smaller clusters show another type of phase transition. The effect of the cluster size and structure on these observations will be discussed.