Effects of electroless deposition conditions on microstructures of cobalt–phosphorous catalysts and their hydrogen generation properties in alkaline sodium borohydride solution

Abstract

Cobalt–phosphorous (Co–P) catalysts with a high hydrogen generation rate in alkaline sodium borohydride (NaBH 4) solution are developed by electroless deposition. The microstructures of the Co–P catalysts and their catalytic activities for hydrolysis of NaBH 4 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 °C exhibit the best hydrogen generation rate of 3300 ml min −1 g −1-catalyst in 1 wt.% NaOH + 10 wt.% NaBH 4 solution at 30 °C, which is 60 times faster than that obtained with a Co catalyst.