TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The catalyst layer formed at the aggregate surface of the metal foam-like support contains rhodium along with component(s) chosen from cerium, zirconium, calcium, magnesium, aluminum, silicon, platinum, nickel and iron. The amount of catalyst layer formed at the surface of metal foam-like support is 30-180 g/L per unit volume.Preferred Structure: The support for the catalyst layer is formed by laminating several metal foam-like supports along the perpendicular direction with respect to the flow direction heating gas. A specific modification catalyst component is supported in some of the metal foam-like support. The diameter of a through-hole contained in the support is set such that the through-hole diameter is reduced from the uppermost support to the lowermost support along the heating gas flow direction. EXAMPLE - 6-fold equivalence of urea was added to aqueous solution of aluminum nitrate nonahydrate (Al(NO3)3.9H2O)), nickel-nitrate hexahydrate and cerium-nitrate hexahydrate, and mixed by stirring. The excess solution was removed by suction filtration, to obtain uniform gel. The obtained gel was dried, to obtain nickel-cerium-alumina gel. The obtained gel was baked at 500degreesC for 4 hours. The baked product was impregnated into aqueous solution of rhodium, and moisture content was evaporated. 6 types of rhodium-nickel-cerium-alumina catalyst containing different amounts of rhodium were prepared. The prepared catalysts were each mixed with water and 1 mass% of nitric acid aqueous solution of alumina sol, to obtain catalyst slurry. 6 types of obtained catalyst slurry were made into 6 types of catalyst support (A-E). The average number of holes in catalyst support (A-E) was 20 ppi (pores/inch), 30 ppi, 40 ppi, 50 ppi, 80 ppi and 120 ppi, respectively. Then, each catalyst support (A-E) was coated to a coating amount of 120 g/L, 100 g/L, 80 g/L, 70 g/L, 60 g/L and 40 g/L, respectively, such that the load of rhodium was approximately 0.8 g/L with respect to all catalyst. The coated catalyst was then baked, to obtain monolith type fuel modification catalyst. The gasoline was effectively modified using the obtained catalyst with fuel conversion ratio of 85% and carbon monoxide concentration of 5.8%.