ZnO- and SiO2-supported palladium catalysts were evaluated in the ethanol steam-reforming and oxidative ethanol steam-reforming reactions in the temperature range 548-723 K. The catalysts were characterized before and after reaction by X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and infrared spectroscopy using CO as a probe molecule. On silica-supported Pd catalyst, ethanol decomposes into H-2, CO and CH4 in both steam-reforming and oxidative steam-reforming reactions. In contrast, ZnO-supported catalysts containing the PdZn phase exhibit a better catalytic performance for hydrogen production through dehydrogenation of ethanol into acetaldehyde and ulterior reforming. (c) 2006 Elsevier B.V. All rights reserved.