Generation of hydrogen by hydrolysis of alkali metal hydrides has attracted attention. Unsupported CoB catalyst demonstrated high activity for the catalytic hydrolysis of NaBH(4) solution. However, unsupported CoB nanoparticles were easy to aggregate and difficult to reuse. To overcome these drawbacks, CoB/SiO(2) was prepared and tested for this reaction. Cobalt (II) acetate precursor was loaded onto the SiO(2) support by incipient-wetness impregnation method. After drying at 100 degrees C, Co cations were deposited on the support. The dried sample was then dispersed in methanol/water solution and then fully reduced by NaBH(4) at room temperature. The catalyst was characterized by N(2) sorption, XRD and XPS. The results indicated that the CoB on SiO(2) possessed amorphous structure. B and Co existed both in elemental and oxidized states. SiO(2) not only affected the surface compositions of CoB, but also affected the electronic states of Co and B. B could donate partial electron to Co. The structure effect caused by the SiO(2) support helped to prevent CoB nanocluster from aggregation and therefore the activity increased significantly on hydrolysis of alkaline NaBH(4) solution. The CoB/SiO(2) catalyst showed much higher activity than the unsupported CoB catalyst. At 298 K, the hydrogen generation rate on CoB/SiO(2) catalyst was 4 times more than that on the unsupported CoB catalyst. The hydrogen generation rate was as high as 10,586 mL min(-1) g(-1) catalyst at 298 K. CoB/SiO(2) is a very promising catalyst for this reaction. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.