Pure hydrogen can be chemically stored and supplied directly to PEFC via the redox of modified fumed-Fe-dust obtained from steel company: storage of H-2 : Fe3O4 + 4H(2) -> 4H(2)O + or Fe2O3(initial state) + 3H(2) -> 2Fe + 3H(2)O; recovery of H-2 : 3Fe + 4H(2)O ->. Fe3O4 + 4H(2). Modified fumed-Fe-dust with various metal additives has been prepared by impregnating metal cations of Cr, Al, Zr, Mo, Mo-Al, Mo-Ti, Mo-Zr, Mo-ce, Mo-Rh, Mo-Ni or Mo-Cu. The reduction of the oxidized fumed-Fe-dust (denoted as FeOx) with and without additives and the performances of formation H-2 of the reduced FeOx-dust have been mainly investigated. The results show that: (1) among the metal additives tested, Mo was the most effective element to enhance the rate of H-2 produced in the oxidation with H2O as well as cyclic stability in repeated redox cycles for oxidized fumed-Fe-dust at low temperature 354 degrees C; (2) the state of additive Mo in oxidized FeOx was suggested to be the chemical composition of 2FeO center dot MoO2 based on the result of XRD spectra; (3) the sintering of the particles was one of the factors effecting on the catalytic activity and cycling stability of the modified FeOx, but what kinds of metal additives to be added in FeOx must be much more important for the sample to promote catalytic activity and keep cyclic stability effective. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.