Catalytic ammonia decomposition over Ni-Ru supported on CeO2 for hydrogen production: Effect of metal loading and kinetic analysis
| Autor: | Ilaria Lucentini, Osvaldo Miguel Martinez, I. Serrano, Jordi Llorca, Carlos Daniel Luzi, Germán García Colli |
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| Přispěvatelé: | Universitat Politècnica de Catalunya. Doctorat en Enginyeria de Processos Químics, Universitat Politècnica de Catalunya. Institut de Tècniques Energètiques, Universitat Politècnica de Catalunya. Departament d'Enginyeria Química, Universitat Politècnica de Catalunya. NEMEN - Nanoenginyeria de materials aplicats a l'energia |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Amoníac Hydrogen Física [Àrees temàtiques de la UPC] Process Chemistry and Technology Inorganic chemistry chemistry.chemical_element Ceria catalysts Decomposition Catalysis Ammonia chemistry.chemical_compound Kinetics chemistry Catàlisi Chemisorption Dehydrogenation Ammonia decomposition Bimetallic catalysts Bimetallic strip Nickel-ruthenium General Environmental Science Hydrogen production |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) |
| Popis: | Ceria-supported Ni-Ru bimetallic catalysts with different metal loadings have been prepared by co-impregnation, characterized and tested in the production of hydrogen from the catalytic decomposition of ammonia. The bimetallic catalysts showed an excellent catalytic performance in long-term stability tests with respect to monometallic Ru/CeO2 and Ni/CeO2 and in multicycle tests under pure ammonia. The best catalytic performance has been obtained over catalysts with 2.4-5 wt.% Ni, 0.4-0.6 wt.% Ru, and a Ni/Ru wt.% ratio of ca. 7. TOFH2 values exceeding 2 s-1 have been obtained, which are among the highest reported for ammonia decomposition at 400 °C. Raman spectroscopy, XRD, HRTEM, XPS, TPR and H2 chemisorption have revealed the existence of an intimate contact between Ni and Ru and CeO2, which is considered the reason of the excellent catalytic activity and stability observed. A kinetic model has been developed using the Langmuir-Hinshelwood-Hougen-Watson approach for the decomposition of ammonia in a fixed bed reactor. The reaction rate expression of the ammonia decomposition on Ni-Ru bimetallics supported on ceria suggests that the dehydrogenation of the ammonia adsorbed on the surface of the catalyst is the limiting step of the reaction and that ammonia decomposition is inhibited by the presence of H2. |
| Databáze: | OpenAIRE |
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