Optimization of nickel loading of mixed oxide catalyst ex -hydrotalcite for H 2 production by methane decomposition
| Autor: | Cristina García-Sancho, Laura Pascual, Pedro Maireles-Torres, R. Guil-López, J.L.G. Fierro, Rufino M. Navarro |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Hydrogen
Hydrotalcite Process Chemistry and Technology Inorganic chemistry chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Catalysis 0104 chemical sciences law.invention Nickel chemistry law Desorption Mixed oxide Calcination 0210 nano-technology Hydrogen production |
| Zdroj: | Applied Catalysis A: General. 548:71-82 |
| ISSN: | 0926-860X |
| Popis: | Hydrogen production free of CO and CO 2 was carried out by methane decomposition process using Ni-mixed oxides from hydrotalcite like-materials ( ex -HTs) as catalysts. The chemical composition was changed in order to evaluate the influence of the Ni-loading on the main physicochemical (ICP-AES, XRD, XPS, TPR, adsorption/desorption of N 2 at 77 K and CO 2 -TPD) properties and on the catalytic performance. For all Ni-loadings (from 7.5 to 58 atomic%), the hydrotalcite structure was the only precursor. After calcination at 850 °C, different mixed oxides were formed as a function of Ni-loading, although Ni-Mg-Al mixed oxide matrix or non-stoichiometric spinel phase was the main phase for all catalysts, with the exception of the 58 Ni atomic% sample, in which the NiO segregated from the Mg-Al matrix was the main phase. Methane conversion close to 55% was achieved, hydrogen was the only gaseous product. The most active catalyst was that containing 46% Ni at. Transmission Electron Microscopy (TEM) images of the spent catalysts showed the appearance of multiwall carbon nanotubes (MWCNTs) although under severe reaction conditions, e.g. high temperatures for thermo-programmed temperature experiments, and the long reaction times for isothermal experiments produced low quality MWCNTs. |
| Databáze: | OpenAIRE |
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