Hydrogen generation from Al/NaBH4 hydrolysis promoted by Co nanoparticles and NaAlO2 solution

This study evaluated hydrogen generation through the hydrolysis of an Al/NaBH4/Co/NaAlO2 system. Hydrogen generation performance can be altered by changing the Al/NaBH4 mass ratios, Co amount and NaAlO2 concentration. The optimized composite can achieve a hydrogen yield of more than 90% within 30 min. Thus, a high hydrogen generation amount and a stable solution pH were achieved. The kinetic analysis results of the Al/NaBH4/Co/NaAlO2 system show that the hydrolysis kinetic is affected by composition design. An activation energy of 53.3 kJ/mol was obtained from 0.2 g Al/0.2 g NaBH4/0.06 g Co nanoparticles/4 mL 0.4 M NaAlO2 solution, which confirms the control exerted by the chemical step. The improved hydrogen generation performance is attributed to the interaction of Al/NaBH4 hydrolysis and the synergistic catalytic effect of Co nanoparticles and NaAlO2. Thus, the mechanism that unifies the behavior of Al/NaBH4 hydrolysis, which is activated by Co nanoparticles and NaAlO2, is presented. As a potential hydrogen source, the Al/NaBH4/Co/NaAlO2 system can be applied for portable fuel cells with high hydrogen generation density and low cost compared with a conventional NaBH4 alkaline solution.