Magnetically recyclable Fe@Co core-shell catalysts for dehydrogenation of sodium borohydride in fuel cells

Co-based catalysts of the reaction by which hydrogen was obtained from NaBH4 solution were prepared by chemical reduction in a liquid phase. X-ray diffraction and scanning electron microscopy analyses showed that the as-prepared Fe@Co catalyst was ultrafine and amorphous. The calculated Arrhenius activation energy of the Fe@Co catalyst was 35.62(1) kJ mol−1 while that of the Co catalyst was 38.81(2) kJ mol−1, demonstrating that Fe@Co nanoparticles reduce the activation energy of the reaction more than does a Co nanocatalyst. X-ray absorption spectroscopy (XAS) clearly reveals the valences of Fe and Co. The Fe valence of Fe@Co is smallest among three catalysts because of the Co shell. The molar ration of Fe to Co is 1: 2 as determined by using XPS analysis, indicating that the novel catalyst reduces costs. The generation of hydrogen is schematically elucidated.

► Replacement of Fe with core-shell modification as compared with only Co could facilitate the catalytic reaction.
► Calculated Arrhenius activation energy demonstrates that Fe@Co nanoparticles reduce the activation energy.
► The easy recycle by a magnet is convenient after the reaction.
► The replacement of Fe reduces the amount of Co, decreasing the cost of the synthesis.