Cu, Mg and Co effect on nickel-ceria supported catalysts for ethanol steam reforming reaction

چکیده مقاله

Ethanol steam reforming is a promising reaction which produces hydrogen from bio and synthetic ethanol. In this study, the nano-structured Ni-based bimetallic supported catalysts containing Cu, Co and Mg were synthesized through impregnation method and characterized by XRD, BET, SEM, TPR and TPD analysis. The prepared catalysts were tested in steam reforming of ethanol in the S/C = 6, GHSV of 20,000 mL/(gcat h) at the temperature range of 450–600 °C. Among the xNi/CeO2 (x = 10, 13, 15 wt%) catalyst, the sample containing 13 wt% Ni with surface area of 64 m2/g showed the best performance with 89% ethanol conversion and 71% H2 selectivity as well as low CO selectivity of 8% at 600 °C and The addition of Cu, Mg, and Co to catalyst structure were evaluated and it was found that the nature of second metal has a strong influence on the catalyst selectivity for H2 production. Considering to results of TPR analysis, the 13Ni–4Cu/CeO2 catalyst showed proper reduction which caused in better activity. On the other side based on TPD analysis, the more basic property of 13Ni–4Mg/CeO2 bimetallic catalyst provided a better condition to methane steam reforming, leading to lower CH4 selectivity and consequently more H2 production. The 13Ni–4Cu/CeO2 exhibited the highest activity and lowest selectivity towards ethanol conversion and CO production about 99% and 4%, while the 13Ni–4Mg/CeO2 catalyst possessed the highest H2 selectivity and lowest CH4 selectivity about 74% and 1% respectively at 600 °C. The Ni–Cu and Ni–Mg bimetallic catalysts shows good stability with time on stream.