Metal oxide nanowires and carbon-coated metal nanowires are effective as supports for particles of an expensive catalyst material, such as platinum metal group catalyst. Such supported catalysts are useful when included in an electrode on, for example, a proton exchange membrane in a hydrogen/oxygen fuel cell. For example, tin oxide nanowires are formed on carbon fibers of carbon paper and platinum nanoparticles are deposited on the tin oxide nanowires. The nanowires provide good surfaces for effective utilization of the platinum material.