Design of NiAl2O4 cellular monoliths for catalytic applications
| Autor: | Andrei V. Kovalevsky, Jorge R. Frade, João C.C. Abrantes, N. Vitorino, Marta C. Ferro |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Mechanical Engineering Metallurgy Spinel Sintering Nanoparticle 02 engineering and technology engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology Heterogeneous catalysis 01 natural sciences 0104 chemical sciences Catalysis Chemical engineering Mechanics of Materials Phase (matter) engineering lcsh:TA401-492 General Materials Science lcsh:Materials of engineering and construction. Mechanics of materials 0210 nano-technology Porosity Stoichiometry |
| Zdroj: | Materials & Design, Vol 117, Iss, Pp 332-337 (2017) |
| ISSN: | 0264-1275 |
| Popis: | This work focuses on designing highly-porous cellular NiAl2O4-based spinel 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. Keywords: Spinel, NiAl2O4, Steam reforming, Ni catalyst, Cellular ceramics |
| Databáze: | OpenAIRE |
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