Improving the ceria-mediated water and carbon dioxide splitting through the addition of chromium
| Autor: | Robert Büchel, Sotiria Mostrou, Jeroen A. van Bokhoven, Sotiris E. Pratsinis |
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| Rok vydání: | 2017 |
| Předmět: |
Hydrogen
Process Chemistry and Technology Inorganic chemistry Oxide chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Catalysis Chromia 0104 chemical sciences chemistry.chemical_compound Chromium chemistry 0210 nano-technology Syngas Hydrogen production Carbon monoxide |
| Zdroj: | Applied Catalysis A: General. 537:40-49 |
| ISSN: | 0926-860X |
| Popis: | The solar thermochemical water and carbon dioxide splitting, mediated by ceria, has a great potential to produce “green” syngas. Chromium was added to ceria to improve the syngas production. Three preparation methods were applied, resulting in different morphologies allowing to investigate the role of chromium. The samples were characterized by X‐ray diffraction, Raman and X-ray spectroscopy, and electron microscopy. Materials made by polymerized-complex-method and dry-impregnation consisted of two crystal phases: ceria and chromia. In contrast, materials made by flame-spray pyrolysis exhibited a homogeneous Cr-doped ceria phase, and chromia was found only at a chromium-content higher than 25 mol%. The chromium-doped ceria released additional oxygen during the formation of CeCrO 3 perovskite, which did not enhance hydrogen or carbon monoxide production. All chromia-containing samples exhibited improved oxygen exchange capacity, possibly due to a redox cycle of chromia itself, and significantly improved the activity of water and carbon dioxide splitting. Hydrogen production increased from 3.2 to 6.7 mL/g and the time to reach redox equilibrium was shorten from 41 to 3 min. The best hydrogen and carbon dioxide production rates were up to 20 and 500 times higher than pure ceria, respectively. The presence of chromium is therefore crucial as a catalyst, promoter, and oxygen storage enhancer. This work emphasises the importance of a catalysed re‐oxidation reaction and demonstrates that a metal oxide, becoming active in situ , can catalyse water and carbon dioxide splitting. |
| Databáze: | OpenAIRE |
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