The steam reforming of ethanol was studied at 400degreesC on Co/Al2O3 and Co/SiO2 catalysts with a cobalt content of 8 and 18% (w/w), respectively. Catalysts were prepared by the impregnation method and characterized by atomic absorption spectroscopy, Raman spectroscopy, and temperature-programmed reduction with hydrogen. The results indicated the presence of Co3O4 as the main phase of cobalt and COO, species interactions with alumina. The catalysts showed average conversion higher than 70% for the steam reforming of ethanol at 400degreesC. The increase of ethanol conversion and reduction of the amount of liquid products were observed for the catalysts with higher cobalt contents. The CO concentration in the gaseous mixture is reduced to 800 ppm levels for the Co/Al2O3 catalyst with 18% of cobalt. During ethanol reformation, the CO produced can react with water (water gas shift, WGS) or hydrogen (methanation, without water) on Co sites. Both reactions, WGS and methanation, allows high conversion on the Co/Al2O3 and Co/SiO2 catalysts, but Co/Al2O3 shows better CO removal. (C) 2004 Elsevier B.V. All rights reserved.