Design of NiAl2O4 cellular monoliths for catalytic applications
authors Vitorino, NMD; Kovalevsky, AV; Ferro, MC; Abrantes, JCC; Frade, JR
nationality International
journal MATERIALS & DESIGN
author keywords Spinel; NiAl2O4; Steam reforming; Ni catalyst; Cellular ceramics
keywords NICKEL ALUMINATE CATALYSTS; EMULSIFIED SUSPENSIONS; ELECTRICAL-CONDUCTIVITY; THIN-FILMS; METHANE; SPINELS; STABILITY; SUPPORTS
abstract This work focuses on designing highly-porous cellular NiAl2O4-based spinet ceramics through combined suspension emulsification/reactive sintering and further decoration of the pore surfaces by Ni nanoparticles for potential applications in heterogeneous catalysis. Due to kinetic limitations and specific porous structure, the reduction occurs without affecting the integrity of the cellular monoliths. The reaction mechanism, assessed by XRD and TEM/ EDS, includes both partial decomposition and reduction, resulting in the formation of metastable Al-enriched phases, mainly NiAl32O49, and metallic Ni phase, respectively. The results suggest that the cellular bulk framework can be decorated with Ni catalyst in a controlled way, by proper selection of the initial cation stoichiometry of the NiAl2O4 spinel and appropriate reduction conditions. In selected conditions the reduction results in Ni nanoparticles of various dimension scales, finely dispersed at the pore surfaces, with a significant fraction below 50 nm, as confirmed by TEM/EDS. The results of thermodynamic analysis emphasize that the redox tolerance of the spinel phase is dependent on the Ni:Al activity ratio, suggesting the prospects for tuning the catalytic activity and stability by designing the initial composition and resulting content of metallic Ni and Ni- and Al-containing metastable phases. (C) 2017 Elsevier Ltd. All rights reserved.
publisher ELSEVIER SCI LTD
issn 0264-1275
isbn 1873-4197
year published 2017
volume 117
beginning page 332
ending page 337
digital object identifier (doi) 10.1016/j.matdes.2017.01.003
web of science category Materials Science, Multidisciplinary
subject category Materials Science
unique article identifier WOS:000394068800037

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