Investigation of iron oxide reduction by ethanol as a potential route to produce hydrogen

In this work, a novel way to indirectly store and produce H-2 from ethanol was investigated using a two-step process based on the reduction of iron oxide followed by oxidation with H2O. The reduction of different iron oxides, i.e., Fe2O3, Fe3O4 and FeOOH, with ethanol to produce Fe was investigated. TPRe (Temperature Programmed Reactions) and Mossbauer and XRD analyses showed that ethanol reduces Fe2O3 sequentially to Fe3O4 at 350-500 degrees C, to Fe3O4/FeO at 500-600 degrees C and finally to Fe at 700 degrees C. The formed Fe can then be oxidized by H2O to produce H-2 and Fe3O4, as shown by Mossbauer and XRD analyses. Cyclic experiments showed that iron could be consecutively reduced/oxidized at least 5 times without any significant decrease in H-2 production after the second cycle. However, reactions of Fe2O3 with ethanol at higher temperatures, i.e., 800 and 900 degrees C, led to the formation of iron carbide and significant carbon deposition. XPS, SEM, TEM, Raman and TG showed 24-28 wt% carbon content, particularly on the surface as nanofibers and as amorphous and graphitic carbon. (C) 2012 Published by Elsevier B.V.