Cobalt-phosphorous (Co-P) catalysts with a high hydrogen generation rate in alkaline sodium borohydride (NaBH4) solution are developed by electroless deposition. The microstructures of the Co-P catalysts and their catalytic activities for hydrolysis of NaBH4 are analyzed as a function of the electroless deposition conditions such as the pH and temperature of the Co-P bath. The electroless-deposited Co-P catalysts are composed of nano-crystalline Co, and amorphous Co-P. The size of the nano-crystalline Co particles dispersed in amorphous Co-P matrix depends largely on the electroless deposition conditions. Moreover, Co-P catalysts with finer crystalline Co exhibit a higher hydrogen generation rate. In particular, the Co-P catalysts formed in a pH 12.5 bath at 60-70 degrees C exhibit the best hydrogen generation rate of 3300 ml min(-1) g(-1) -catalyst in 1 wt.% NaOH + 10 wt.% NaBH4 solution at 30 degrees C, which is 60 times faster than that obtained with a Co catalyst. (C) 2008 Elsevier B.V. All rights reserved.