Effect of Co+2/BH4− ratio in the synthesis of Co–B catalysts on sodium borohydride hydrolysis

• A set of Co–B catalysts prepared with different Co(II) and BH4− ratio.
• Physical and chemical properties of Co–B were investigated.
• Catalysis of sodium borohydride solution was performed at different NaOH and NaBH4 concentrations.

Cobalt boride is known to act as a catalyst to facilitate the hydrolysis reaction of sodium borohydride. The catalytic nature of cobalt boride is immensely dependent upon the synthesis procedure and reaction conditions used, especially on the relative amount of Co(II) and borohydride used for catalyst preparation. In the current work a set of catalysts were prepared by varying the cobalt(II) and borohydride ratio in the reactant solution. The prepared catalysts were well characterized using different characterizing tools like XRD, FTIR, FEG-SEM, FEG-TEM, ICP-AES and XPS. The effect of the catalyst on the hydrolysis of sodium borohydride was thoroughly studied and reported in the current work. The catalytic activity of the catalyst was observed to be highly dependent on the reduced cobalt content. It was observed that the excess amount of borohydride used to synthesize the catalyst, was not increasing the catalytic activity after the complete reduction of cobalt.