TECHNOLOGY FOCUS - METALLURGY - Preferred Method: The methanation catalyst is prepared by precipitation, hydrothermal synthesis, or sol-gel method; is reduced by vapor phase or liquid phase reduction; and is post-treated with heat treatment under hydrogen atmosphere at 200-500degreesC for 1-12 hours. The methanation catalyst and a preferential oxidation (PROX) catalyst are integrated. Preferred Materials: The non-precious metal particles are cobalt (Co) and/or nickel (Ni). The metal oxide particles are CoOx or NiOx. The PROX catalyst is copper oxide-cesium oxide, platinum nickel/gamma-aluminum oxide, platinum-cobalt/gamma-aluminum oxide, or platinum-cobalt/yttria stabilized zirconia (YSZ). The non-precious metal particles comprise a transition metal.x=1-2.Preferred Compositions: A mole ratio of the metal oxide particles to the metal particles is 0-1, preferably 0-0.4. The mixture of Co and Ni comprises 10-90 pbw of Ni and nickel oxide. The PROX catalyst is 5-50 vol.%. Oxygen introduced to the CO removal unit is 0.5-1.5, preferably 0.75-1 times as much as the concentration of CO. Preferred Properties: The non-precious metal particles have average particle size of 2-500 nm. Preferred Conditions: An operating temperature of the methanation catalyst is 100-180degreesC at less than 1% CO. The CO is removed at less than or equal to200, preferably 100-180degreesC. A space velocity of a fuel supplied to the CO removing catalyst system is less than 1000, preferably less than 200 ml/minute/gcat. EXAMPLE - About 80 g of cobalt nitrate was mixed with 80 ml of deionized water. The mixture was stirred. A 1M sodium hydroxide was added dropwise to the cobalt nitrate solution to adjust the mixture to a pH of 8-9. The mixture was ripened at 70-80degreesC for 1 hour, and the mixture was filtered and washed using deionized water to reach a pH of 7. Then, the mixture was dried in an oven at 110degreesC for 10 hours, and reduced at 300degreesC for 1 hour under an atmosphere of hydrogen gas to prepare crystalline, active catalyst metal particles and an oxide of the active catalyst metal.