Catalytic production of hydrogen from steam reforming of methanol on CeO2 promoted Cu/Al2O3 catalysts

Catalytic production of hydrogen by steam reforming of methanol has been studied on a series of co-precipitated CeO2 promoted Cu/Al2O3 catalysts under atmospheric pressure in a microreactor. Cu/CeO2/Al2O3 catalysts displayed higher activity and stability than that of Cu/Al2O3 catalysts. Maximum methanol conversion of 95.5% and H-2 selectivity of 100% were obtained at 250 degreesC, n(H2O)/n(CH3OH) = 1/1, WHSV = 3.28 h(-1), with the catalyst containing mass fraction 20% of CeO2. After 200 h of reaction, methanol conversion was still over 90.0% with CeO2 promoted Cu/Al2O3 catalyst, while the activity of Cu/Al2O3 catalyst deactivated rapidly after 100 h of reaction. XRD and TPR results indicated that CeO2 promoter not only greatly improved the surface copper dispersion, and prevented copper crystallites from reuniting or sintering, but also made copper crystallites relatively smaller and promoted copper reduction. In addition, CeO2 could enhance water gas shift reaction, which led to the decrease of CO concentration in the reformed gases. It is suggested that the high activity, selectivity and stability of Cu/CeO2/Al2O3 catalysts are resulted from higher copper dispersion and smaller copper crystallites, and the synergetic effect between copper and ceria.