Hydrogen Production from Ethanol Steam Reforming over Noble Metal Catalysts Supported on SiO2: Mechanism of Methane Production and Reaction Conditions for Suppression of Methane Production

We investigated ethanol steam reforming over Rh/SiO2, Pt/SiO2, Pd/SiO2, and Ru/SiO2 at 573-723 K using a fluidized-bed quartz reactor to determine which reaction conditions suppressed CH4 production and increased H-2 and CO2 production. At temperatures under 623 K over Rh/SiO2 and Ru/SiO2. CH4 was produced not only by ethanol decomposition but also by the reduction of CO2 and CO to CH4. At 723 K, the product yields over all four catalysts were strongly influenced by the partial pressure of ethanol: CH4 production was suppressed, and H-2 and CO2 production was increased, at low partial pressure of ethanol. These experimental results can be explained in terms of the partial pressures of CO2 and H-2.