Hydrogen storage properties of modified fumed-Fe-dust generated from a revolving furnace at a steel industry

摘要

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 : Fe_3O_4 + 4H_2 → 3Fe + 4H_2O or Fe_2O_(3(initial state)) + 3H_2 → 2Fe + 3H_2O; recovery of H_2 : 3Fe + 4H_2O → Fe_3O_4 + 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 FeO_x) with and without additives and the performances of formation H_2 of the reduced FeO_x-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 H_2O as well as cyclic stability in repeated redox cycles for oxidized fumed-Fe-dust at low temperature 354℃; (2) the state of additive Mo in oxidized FeO_x was suggested to be the chemical composition of 2FeO • MoO_2 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 FeO_x, but what kinds of metal additives to be added in FeO_x must be much more important for the sample to promote catalytic activity and keep cyclic stability effective.