Surface Ostwald ripening of Pd nanoparticles on the MgO (100) surface

Morphological changes of Pd nanoparticles on the (100) surface of MgO single crystal were investigated by Auger electron spectroscopy in the temperature range of 873–983 K. The size and distribution of clusters were also examined by means of atomic force microscopy. It was shown that there was practically no decrease of the effective thickness of deposited Pd during heat treatments under 6×10-9 mbar. Assuming that the observed change in the Auger intensities is due to the surface Ostwald ripening the temperature dependence of the surface mass transport diffusion coefficients can be given as D′ s=(1.6+8.2 -1.34)×10-8exp((-(136±15) kJ mol-1)/(RT))m2 s-1 .