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Characterization and catalytic behavior of hydrotalcite-derived Ni–Al catalysts for methane decomposition
- Source :
- International Journal of Hydrogen Energy. 45:17299-17310
- Publication Year :
- 2020
- Publisher :
- Elsevier BV, 2020.
-
Abstract
- A series of Ni catalysts were prepared from Ni–Al hydrotalcite-like compounds (HTlcs) by varying the Ni/Al molar ratio (1–4) and calcination temperature (773–1173 K) of HTlcs. The catalysts were reduced with H2 at 1073 K and tested for CH4 decomposition at 773–923 K on a thermal gravimeter. Various techniques including N2 physical adsorption, XRD, H2-TPR, XPS, HAADF-STEM, TEM, and Raman were applied to characterize the catalysts and the as-produced carbon. The characterizations show that calcination of Ni–Al HTlcs leads to Ni(Al)O solid solution and minor NiO and/or NiAl2O4 spinel may be formed depending on the Ni/Al ratio and calcination temperature; upon reduction at 1073 K, most nickel species are reduced to metallic Ni. In CH4 decomposition, carbon yield shows a volcano-type dependence on the Ni content with the optimum Ni/Al ratio equal to 3. On the other hand, carbon yield is affected by the calcination temperature of the Ni3Al HTlcs to a small extent. Carbon yield is also significantly affected by the reaction temperature, which decreases remarkably with a rise of temperature to 923 K. TEM and Raman indicate that fish-bone carbon nanofibers are formed at 773–823 K, whereas multi-walled carbon nanotubes are formed at 873–923 K.
- Subjects :
- Materials science
Hydrotalcite
Renewable Energy, Sustainability and the Environment
Carbon nanofiber
Energy Engineering and Power Technology
chemistry.chemical_element
02 engineering and technology
Carbon nanotube
010402 general chemistry
021001 nanoscience & nanotechnology
Condensed Matter Physics
01 natural sciences
Decomposition
0104 chemical sciences
Catalysis
law.invention
Nickel
Fuel Technology
chemistry
Chemical engineering
law
Calcination
0210 nano-technology
Carbon
Subjects
Details
- ISSN :
- 03603199
- Volume :
- 45
- Database :
- OpenAIRE
- Journal :
- International Journal of Hydrogen Energy
- Accession number :
- edsair.doi...........1047769e3cef7d33fee4e6cc56601f84