Production of hydrogen by steam reforming of methanol on CeO2 promoted Cu/Al2O3 catalysts

Catalytic production of hydrogen by steam reforming of methanol reaction has been developed on a series of co-precipitated Cu/Al2O3 catalysts promoted with CeO2 at atmospheric pressure in a microreactor. Effects of CeO2 content, reaction temperature, methanol space velocity and H2O/CH3OH molar ratio on the catalytic activity have been investigated. CeO2 promoted Cu/Al2O3 catalysts exhibited higher activity and stability as compared to the unpromoted ones. The catalyst containing 20 wt.% of CeO2 was the most active one with a methanol conversion of 95.5 mol%, H-2 selectivity of 99.9 mol% and the outlet CO concentration of 0.14 mol% at 250degreesC. After 200 h of reaction, methanol conversion was still over 90.0% with the catalyst containing 20 wt.% of CeO2, while Cu/Al2O3 catalyst deactivated rapidly after 100 h of reaction. Results of X-ray diffraction (XRD) and the surface element distribution of catalysts showed that CeO2 not only greatly improved the surface copper dispersion and prevented copper crystallites from conglomeration or sintering, but also made copper crystallites relatively smaller. The improvement in activity and stability of the promoted catalysts was attributed to higher copper dispersion and smaller copper crystallites, and the synergetic effect of ceria. (C) 2002 Elsevier Science B.V. All rights reserved.