A monolithic Cu-Ni-based catalyst was fabricated by partial reduction reaction of a solid solution of (Cu, Ni, Mg)O. The deposited Cu-Ni particles, 5-10 nm in diameter, were embedded in (Ni, Mg)O ceramic substrate, and dispersed homogeneously. CO2 reforming of methane and steam reforming of methanol were conducted using this catalyst. Although the amount of the deposited Cu-Ni particles was quite small (0.84 wt.% of the total weight), the catalyst showed a high reforming activity in both reforming reactions. In the case of the CO2 reforming of methane, methane (methane/CO2 = 1/1) was converted at 800 degreesC to 44 vol.% H-2, 49 vol.% CO, 5 vol.% CH4, and 2 vol.% CO2 at a space velocity of 1734 h(-1). In the case of the steam reforming of methanol, methanol (steam/methanol = 4/1) was converted at 400 degreesC to 70 vol.% H2, 22 vol.% CO2, and 7 vol.% CO at a space velocity of 2601 h(-1), whereas methanol (steam/methanol = 2/1) was converted at 400 degreesC to 64 vol.% H-2,17 vol.% CO2,9 vol.% CO, and 4 vol.% CH4 at a space velocity of 1613 h(-1). These high activities of the fabricated catalyst were mainly attributed to the dispersed Cu-Ni nanoparticles, which effectively worked in the reforming reactions. (C) 2004 Elsevier B.V. All rights reserved.