Catalytic generation of hydrogen by steam reforming of acetic acid over a series of Ni-Co catalysts have been studied. The catalyst with the molar ratio of 0.25:1 between Ni and Co was superior to other catalysts. The effects of reaction temperature, liquid hourly space velocity (LHSV) and molar ratios of steam-to-carbon (S/C) were studied in detail over this catalyst. At T=673 K, LHSV = 5.1 h(-1), S/C = 7.5:1, the catalyst exhibited the best performances. Acetic acid was converted completely to hydrogen, while H-2 selectivity reached up to 96.3% and CO2 selectivity up to 98.1% was obtained, respectively. Ni-Co catalyst showed rather stable performances for the 70 h time-on-stream without any deactivation. (c) 2006 Elsevier B.V. All rights reserved.