Ni/Mg–Al mixed oxide catalyst for the steam reforming of ethanol
A series of 10 wt% Ni-loaded Mg–Al mixed oxide supported catalysts were evaluated for the production of hydrogen via the steam reforming of ethanol. Mg–Al mixed oxide supported nickel catalysts were found to give superior activity, H2 and COx product selectivity, and improved catalyst stability compared to the pure oxide supported nickel catalysts. Performance was dependent upon the Al and Mg content of the support. At 923 K, the mixed oxide supported catalysts exhibited the highest H2 and COx yields and were stable, showing no signs of deactivation after 20 h of operation. The improved performance of these catalysts was related to the incorporation of the pure oxides, MgO and Al2O3, into a MgAl2O4 phase. The formation of MgAl2O4 reduced nickel incorporation into the supports leaving nickel in its active form. In addition, the formation of MgAl2O4, a slightly basic material, exhibited moderate acidic and basic site strength and density compared to the pure oxide supported catalysts. Moderation of the acid–base properties improved the activity, selectivity, and stability of the catalysts by reducing activity for by-product reactions.