Size-tailored Ru nanoparticles deposited over γ-Al 2 O 3 for the CO 2 methanation reaction
By means of the polyol method, a series of 5 wt% Ru/Al 2 O 3 catalysts was synthesized controlling the particle size of the ruthenium species. The physico-chemical characterization demonstrated the successful particle size control of the Ru species, in such a way that higher the Ru/PVP ratio, higher...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | Universidad de Sevilla (US) |
| Repositorio: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:idus.us.es:11441/170258 |
| Acceso en línea: | https://hdl.handle.net/11441/170258 https://doi.org/10.1016/j.apsusc.2019.03.248 |
| Access Level: | acceso abierto |
| Palabra clave: | Carbon capture and utilization (CCU) CO 2 methanation CO 2 methanation mechanism High-pressure effect Methane production Ru nanoparticles Ru/Al 2 O 3 catalysts Sabatier reaction |
| Sumario: | By means of the polyol method, a series of 5 wt% Ru/Al 2 O 3 catalysts was synthesized controlling the particle size of the ruthenium species. The physico-chemical characterization demonstrated the successful particle size control of the Ru species, in such a way that higher the Ru/PVP ratio, higher the Ru particle size. Moreover, there are evidences that suggest preferential growth of the RuO 2 clusters depending on the Ru/PVP ratio. Regarding the catalytic activity during the CO 2 methanation, the total conversion and the CH 4 yield increased with the particle size of Ru. Nevertheless, a considerable enhancement of the catalytic performance of the most active system was evidenced at 4 bar, demonstrating the improvement of the thermodynamics (superior total conversion) and kinetics (superior reaction rate) of the CO 2 methanation at pressures above the atmospheric one. Finally, the in situ DRIFTS study allowed to establish that CO 2 was dissociated to CO* and O* species on the metallic Ru particles, followed by the consecutive hydrogenation of CO* towards CHO*, CH 2 O*, CH 3 O*, and finally CH 4 molecules, which were further desorbed from the catalyst. Thus from the mechanistic point of view, a suitable particle size of the Ru nanoparticles along with the high-pressure effects results in the enhancement of the availability of hydrogen and consequently in the formation of CH x O species that enhance the cleavage of the C–O bond, which is the rate-determining step of the overall CO 2 methanation process. |
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