The steam reforming of methane to produce hydrogen as an energy source for use in a proton exchange membrane fuel cell over Ce-ZrO2-supported Ni, Pt, Ru and Rh catalysts was studied. In order to select highly active and stable reforming catalysts for use in a membrane reactor, methane conversion and CO selectivity were determined in a low-temperature range of 500-800 degreesC. Among the structures of Ce1-xZrxO2 support with a 10 wt.% Ni loading, the Ce0.15Zr0.85O2 showed the highest CH4 conversion at 500-600 degreesC and a high H-2/CO ratio due to the oxidation of CO via the water-gas shift reaction. The catalytic activity Of Ce1-xZrxO2-supported catalyst can be further improved by loading with Pt, Ru and Ph. The highest activity was obtained for a Rh/Ce0.15Zr0.85O2 catalyst for which the methane conversion was 28.1% at 500 degreesC. (C) 2004 Elsevier B.V. All rights reserved.