Methanol reforming for fuel-cell applications: Development of zirconia-containing Cu-Zn-Al catalysts

The steam reforming of methanol to form mixtures of carbon dioxide and hydrogen, together with traces of carbon monoxide, is considered to be a potential source of hydrogen as the fuel for a fuel-cell to be used in mobile power sources. After outlining some of the constraints inherent in the use of the reaction and the types of catalysts which have been used by other investigators, this paper presents results on the preparation and testing of a series of copper-containing catalysts for this reaction. It is shown that the reaction sequence probably involves the formation of methyl formate which then decomposes to give CO₂ as the primary product; CO is formed by the reverse water-gas shift reaction and this only occurs to an appreciable extent when the methanol is almost completely converted. A number of different copper-containing catalysts are then described and it is shown that of these sequentially precipitated Cu/ZnO/ZrO₂/Al₂O₃ materials have the highest activities and stabilities for the steam reforming reaction.