Pd particles were prepared from Pdcl(2) solution (>10(-3) M) in the presence of methanol, ethanol or 2-propanol using Co-60 radiation source to generate solvated electrons and organic reducing radicals. Temperature programmed oxidation (TPO), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) have been used to characterize Pd particles. Radiolytic and thermal reduction of Pd2+ appears to take place simultaneously resulting in the extensive poisoning of Pd sites as confirmed by TPO. The relatively high intensity of the C 1s spectra at 287-290 eV binding energy (BE) confirms the presence of keto and carboxylic groups on the surface. Faceted particles decorated with smaller ones have been observed by TEM measurements. Hydrogenation of 1-octyne in n-heptane has been used as a test reaction to characterize the surface sites. The increasing hydrogenation activity in repeated experiments can tentatively be explained by partial removal of surface impurities and by disintegration some of the adhered particles upon the corrosive action of 1-octyne. (C) 2004 Elsevier B.V. All rights reserved.