Facile hydrogen generation using colloidal carbon supported cobalt to catalyze hydrolysis of sodium borohydride

Abstract

Colloidal carbon spheres (CCS) obtained from hydrothermal treatment of glucose are employed for the first time as a support for cobalt catalysts (CCS/Co) prepared by impregnation-chemical reduction method. Ultra-fine, almost amorphous cobalt metals bind tightly to the CCS surface and are distributed uniformly, creating highly-dispersed active sites which lead to facile catalysis of the hydrolysis of sodium borohydride in aqueous alkaline solution and rapid generation of hydrogen. An average hydrogen generation rate of 7.5, 8.4 and 10.4 L min−1·gmet−1 is achieved at 20 °C for the CCS/Co catalysts with a Co loading content of 14.00, 15.45 and 18.38 wt%, respectively. The activation energy and enthalpy of the CCS/Co catalyzed NaBH4 hydrolysis are found to be 24.04 and 21.51 kJ mol−1, respectively. The low activation energy and rapid hydrogen generation rate suggest that the CCS-support Co materials are excellent catalysts for hydrogen production from borohydride hydrolysis.