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. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.