Carbon-supported Co-B catalysts with various loading contents were prepared by impregnation-chemical reduction method. The XRD, ICP, SEM and TEM analyses revealed that the as-prepared Co-B catalysts were in amorphous form with the composition Of Co2.0-3.3B and the carbon-supported Co-B catalysts had a good dispersion and coating condition. The hydrogen generation measurement showed that the average hydrogen generation rate at 25 degrees C was 1127.2mL min(-1) g(-1) for unsupported Co-B catalyst, while it was 1268.1, 1482.1 and 2073.1 mL min(-1) g(-1) for the carbon-supported catalysts with the Co-B loading of 30.0, 15.6 and 7.44 wt%, respectively. The activation energy of the 30.0 wt% Co-B loading catalyst for the hydrogen generation reaction was measured to be 57.8 kJ mol(-1). Compared with the unsupported Co-B catalyst, the as-prepared carbon-supported catalysts presented higher activity for hydrolysis of NaBH4 aqueous solution, indicating their potential application in mobile hydrogen production for fuel cells. (c) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.