Methanol steam reforming over ex-hydrotalcite Cu-Zn-Al catalysts

Cu-ZnO-Al2O3 catalysts have been prepared via hydrotalcite-like hydroxycarbonate precursors and tested in the oxidative steam reforming of methanol (MOSR) to produce hydrogen with poor CO content. The surface chemistry of the catalysts has been investigated by IR spectroscopy of low temperature CO adsorption. The aim was to gain indications on the optimal catalyst composition for MOSR and on the role of the CO into CO2 conversion step. The conclusions are that the catalytic activity is almost independent on the copper content in the range 5-12% (atomic metal content). The direct oxidation of CO to CO2 by Cu2+ ions is likely a key step both for MOSR and water gas shift over these catalysts. (C) 2006 Elsevier B.V. All rights reserved.