H2 purification through preferential oxidation of CO over ceria supported bimetallic Au-based catalysts

CeO2 supported mono and bimetallic Au catalysts (Au-Ag, Au-Cu, Au-Pd, Au-Ru), prepared by deposition-precipitation, were tested in the preferential oxidation of CO in the excess of H-2 (PROX). Activity data showed that the PROX performances of Au/CeO2 are boosted by addition of Ag and to a minor extent Cu, whereas Ru and Pd have a negative effect. For both Au Ag and Au Cu systems the deposition order did not affect the catalytic performance whereas 1wt%/1wt% was found as the optimal Au/second metal ratio. On the basis of characterization data (H-2-TPR, TG-DTA, DRIFT, Surface Area measurements) it was proposed that the addition of Ag and Cu to Au/CeO2 leads to a higher reactivity of surface ceria oxygen involved in the PROX reaction through a Mars-van Krevelen mechanism. The higher activity of the Au-Ag/CeO2 system was attributed to the occurrence of a strong mutual interaction between gold and silver that positively affects the PROX performance in terms of yields to CO2 and stability under reaction conditions. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.