**5. Conclusion**

Decomposition and desulfurization of AR were examined using *α*-Fe<sup>2</sup> O3 catalyst containing Zr and Al in a steam atmosphere. The catalyst was prepared by coprecipitation method. Heavy oil fraction of AR was decomposed with the catalyst, producing CO<sup>2</sup> , light hydrocarbons, and residue. The lattice oxygen of *α*-Fe<sup>2</sup> O3 reacted with heavy oil at first. Then, oxygen species generated from steam were supplied to the iron oxide lattice and react with heavy oil fraction, producing light hydrocarbons and CO<sup>2</sup> . Hydrogen species generated from steam during the reaction of the oxygen species, and heavy oil fraction supplied to light hydrocarbons, H<sup>2</sup> S, and residue. Supplies of the hydrogen species to light hydrocarbons suppressed alkene generation. Some hydrogen species reacted with sulfur compound of AR, producing H<sup>2</sup> S. Some SO<sup>2</sup> could be generated by the reaction of sulfur compound and oxygen species derived from steam. Consequently, hydrogen species and oxygen species derived from steam reacted with heavy oil fraction and sulfur compound of AR with the *α*-Fe<sup>2</sup> O3 catalyst containing Zr and Al in a steam atmosphere to produce light hydrocarbons.
