Structured catalysts consisting of either undoped or potassium-doped mesoporous Co3O4 nanowires supported on stainless steel wire meshes (SSWM) and prepared by the ammonia evaporation-induced method were tested in the ethanol steam reforming (ESR) reaction. The undoped catalyst was strongly reduced to elemental Co in ESR conditions, causing a decrease in catalytic activity, the undesired formation of acetone, the premature deactivation of the catalyst due to coke deposition and the detachment of particles from the SSWM. Doping the catalyst with potassium (molar K/Co around 0.05) produced an increase in the surface area of the catalysts and a significant enhancement of the catalytic performance in terms of H-2 TOF, carbon selectivity towards CO2 and stability. The presence of potassium prevented the over-reduction of the Co3O4 particles to elemental Co, thereby avoiding the detrimental effects of this phase. Comparison with cobalt-based catalysts described in the literature confirm that the doped catalysts produced in this work are more active and present better values of carbon selectivity towards CO2 than structured catalysts previously reported. (C) 2013 Elsevier B.V. All rights reserved.