Co/Fe3O4@GO catalyst for one-step hydrogen generation from hydrolysis of NaBH4: Optimization and kinetic study.

In this study, cobalt nanocatalysts supported on the Fe 3 O 4 @GO were synthesized for boosting hydrogen generation upon hydrolysis of sodium borohydride. Co/Fe 3 O 4 @GO catalysts were synthesized through a facile co-precipitation method followed by a chemical reduction step. The prepared samples were characterized using various techniques including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM), Vibrating sample magnetometer (VSM), and Nitrogen adsorption–desorption (BET). Benefiting from the high crystallinity, good dispersion of Co nanoparticles over the Fe 3 O 4 @GO, and the synergistic effect between Co nanoparticles and Fe 3 O 4 @GO support, Co/Fe 3 O 4 @GO catalysts with 30 wt% cobalt loading showed the highest catalytic activity with high hydrogen generation rate of 4000 mL/min.g cat and relatively good stability. To investigate the effect of the parameters on hydrogen generation rate and optimal reaction conditions, the Box-Behnken design under response surface methodology (RSM) was applied. ANOVA results denoted that the temperature with the highest F-value and lowest P-value had the most effect on the hydrogen generation rate. Under the optimum conditions including a temperature of 39.83 °C, 17.74 mg of catalyst, and 5.135 wt% NaBH 4 concentration, Co(30%)/Fe 3 O 4 @GO exhibited a superior H 2 generation rate of 6005 mL/min.g cat and low activation energy of 44.4 kJ/mol. Therefore, the Co/Fe 3 O 4 @GO is a promising catalyst for NaBH 4 hydrolysis due to its easy preparation and separation method, high hydrogen generation rate, and low activation energy. [Display omitted] • Fe 3 O 4 /GO was synthesized as a support to promote the Co-based catalyst activity and reusability. • The highest performance was obtained over a catalyst containing 30 wt% of Co nanoparticles. • Response surface methodology (RSM) was carried out to optimize the hydrogen-generation rate reaction conditions. • Over the Co(30%)/Fe 3 O 4 @GO, the activation energy was calculated to be as low as 44.4 kJ/mol. • The maximum hydrogen generation rate (HGR) obtained at optimun condition was 6005 mL/min.g cat. [ABSTRACT FROM AUTHOR]