TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composite: The composite comprises a composition selected from M1Ox-CeO2/C (I) and CeyM1(1-y)O2/C (II).x=1-3;M1=first metal selected from Groups 3-8, 10-14, or 16;y=0.01-0.99.Preferred Catalyst: The catalyst comprises an active particle comprising the composite and the second metal, and where the active particle is disposed on the carbonaceous material. Preferred Method: The method involves: providing a first metal-cerium oxide solid solution; contacting a second metal or a precursor of the second metal with the first metal-cerium oxide solid solution; and heating the solid solution and the second metal to form the catalyst. Preferred Components: The first metal is at least one metal selected from Groups 3-8, 10-14, and 16. The first metal is at least one metal selected from manganese (Mn), vanadium (V), copper (Cu), zinc (Zn), iron (Fe), cobalt (Co), and titanium (Ti), preferably manganese. The solid solution is present in an amount of 5-90 parts by weight, based on 100 parts by weight of the composite. The amount of the first metal is 0.1-1.5 moles, based on 1 mole of cerium of the cerium oxide. The second metal is at least one metal selected from Groups 8-11. The second metal is at least one metal selected from platinum (Pt), palladium (Pd), ruthenium (Ru), iridium (Ir), gold (Au), and silver (Ag). The second metal is an alloy comprising Pd and Ir. The second metal is present in an amount of 1-70 parts by weight, based on 100 parts by weight of the catalyst. EXAMPLE - 1 g Ketjen Black as a carbonaceous material was dissolved in distilled water to prepare a carbonaceous material mixture. 0.729 g (NH4)2Ce(NO3)6, 3.15 g KMnO4 solution, and 0.154 g Mn(NO3)2.6H2O were dissolved in 200 g distilled water to prepare a precursor mixture. A molar ratio of Mn(NO3)2.6H2O, KMnO4, and (NH4)2Ce(NO3)6 was 2:3:5. After mixing the carbonaceous material mixture and the precursor mixture, the pH of the mixture was adjusted to 10 by adding a 2M potassium hydroxide solution. The resulting mixture was aged at a temperature of 80 degrees C, filtered, and rinsed. Then, the aged mixture was dried at a temperature of 110 degrees C to obtain a composite including a carbonaceous material and a manganese-cerium oxide (CeyMn1-yO2) including a cerium oxide and manganese dissolved in the cerium oxide, where an amount of the carbonaceous material in the composite was 73.2 parts by weight, and an amount of the cerium oxide was 17.2 parts by weight. Also, a molar ratio of cerium and manganese in the manganese-cerium oxide was 1:1.