Biomass Gasification with Catalytic Tar Reforming: A Model Study into Activity Enhancement of Calcium- and Magnesium-Oxide-Based Catalytic Materials by Incorporation of Iron

The development of efficient catalysts for the in situ elimination of tar produced in the gasification of biomass represents an important stage in the production of a clean hydrogen-rich gas suitable for use in fuel cells. With this in mind, the incorporation of iron, a readily available, low-cost, and non-toxic material, in calcined dolomite and its constituent compounds, CaO and MgO, was investigated. The Fe/CaO, Fe/MgO, and Fe/dolomite systems were prepared using two impregnation techniques to generate the Fe 2+ and Fe 3+ species, which were then carefully characterized. Tar conversion tests in the presence of these prepared catalysts were carried out in a microreactor, using toluene as the tar model component. The catalysts were characterized before and after the reactor runs [using X-ray diffraction (XRD), temperature-programmed reduction (TPR), and Mössbauer spectroscopy] to better identify the catalytically active phases and the competitive interaction of iron with CaO, MgO, and calcined dolomite under reaction conditions.