Ceria-promoted Ni@Al_2O_3 core-shell catalyst for steam reforming of acetic acid with enhanced activity and coke resistance

摘要

A series of Ni@Al2O3 core-shell catalysts with ceria added to the surface of Ni nanoparticles or inside the alumina shell were prepared, and the effect of ceria addition on the performance of the catalyst in the steam reforming of acetic acid was investigated. The prepared catalysts were characterized by BET, XRD, HRTEM, H-2-TPR and DTG. The addition of ceria to the surface of nickel nanoparticles greatly enhanced the activity of catalyst owing to the presence of the mobile oxygen, which migrated from the ceria lattice. Among the prepared catalysts, the Ni@Al10Ce catalyst showed the highest activity with a conversion of acetic acid up to 97.0% even at a low temperature (650 degrees C). The molar ratio of CO2/CO was also improved due to the oxidation of CO by the mobile oxygen into CO2. The coke formation on the core-shell catalysts was significantly inhibited by the addition of ceria to the surface of nickel nanoparticles due to the oxidation of carbon species by the mobile oxygen in the ceria lattice. However, the Ni@Al10Ce-a catalyst with ceria added to the alumina shell showed a low activity and the formation of a large amount of coke. It is suggested that only the ceria in close to the Ni surface has the promoting effect on the catalytic performance of the Ni@Al2O3 catalyst in the steam reforming of acetic acid. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.