Steam reforming of naphthalene as model biomass tar over iron–aluminum and iron–zirconium oxide catalyst catalysts

In this study the catalytic properties of iron-based mixed metal oxides such as iron–alumina (Fe–Al) and iron–zirconia (Fe–Zr) were investigated at 850 °C in a fixed bed reactor for the steam reforming of naphthalene as a model biomass tar compound. The effects of addition of copper species (CuO) to the iron-based mixed metal oxide catalysts were also examined. For Fe–Al catalysts, the catalytic activities for naphthalene conversion increased with increasing Fe content except for 100Fe–0Al. The catalytic activities of Fe–Al and Fe–Zr were comparable at steady state conditions. Compound oxides were formed in the cases of Fe–Al, but not in Fe–Zr. A strong peak in the vicinity of 2θ = 45° for metallic iron was observed after catalytic experiments in the XRD patterns of all catalysts, which could be related to the active sites of the catalysts. The addition of CuO increased the activities and stability of the Fe–Al catalysts. The reasons for catalytic activity enhancement due to CuO addition can be explained as follows: copper dispersed evenly in the compound oxides facilitate the reduction of iron oxides to metallic iron and prevent the catalytic deactivation due to decrease in surface area of the catalysts during the reaction.