Hydrogen generation by catalytic hydrolysis of sodium borohydride using the nano-bimetallic catalysts supported on the core-shell magnetic nanocomposite of activated carbon

Abstract

The purpose of this study were to prepare the novel supported bimetallic cobalt-nickel catalysts on the core-shell magnetic nanocomposite of activated carbon derived from wood by sequential and co-deposition-precipitation. The performance of the prepared catalyst was evaluated for the hydrogen generation from hydrolysis of sodium borohydride. The magnetic catalysts were characterized by applying the XRD, XPS, FTIR, FESEM, TEM, ICP, BET and VSM tests. The hydrogen generation rate was increased with the reduction of calcination temperature. The well dispersed magnetic nanoparticles were fabricated with average size below of 30 nm which was confirmed by TEM, FESEM and XRD results. The activity of the prepared samples with respect to the preparation method was illustrated to follow a specific order: Co/Ni/MWAC > Ni/Co/MWAC > Co–Ni/MWAC. The developed model derived from design of experiments could correlate the operating parameters with the experimental data while the correlation coefficient was achieved to be 0.99. The hydrogen generation rate was increased with increasing the reaction temperature and the concentration of sodium borohydride in the alkaline solutions. The hydrogen generation rate was measured to be 740.70 ml min−1. gcat−1 in the presence of the Co/Ni/MWAC at 30 °C. The experimental study also indicated that the hydrolysis of sodium borohydride was a zero order type reaction and the activation energy was calculated 40.70 kJ mol−1. The stability of the prepared sample was also investigated for six cycles which showed the acceptable performance of the synthesized catalyst for the practical applications.