The Mitigation of CO Present in the Water–Gas Shift Reformate Gas over IR-TiO<sub>2</sub> and IR-ZrO<sub>2</sub> Catalysts
CO hydrogenation and oxidation were conducted over Ir supported on TiO<sub>2</sub> and ZrO<sub>2</sub> catalysts using a feed mimicking the water–gas shift reformate stream. The influence of the support interaction with Ir and the catalysts’ redox and CO chemisorption propert...
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| Autores principales: | , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
MDPI AG
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/660a069faeab4454a66019e1db497140 |
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| Sumario: | CO hydrogenation and oxidation were conducted over Ir supported on TiO<sub>2</sub> and ZrO<sub>2</sub> catalysts using a feed mimicking the water–gas shift reformate stream. The influence of the support interaction with Ir and the catalysts’ redox and CO chemisorption properties on activity and selectivity were evaluated. Both catalysts oxidised CO to CO<sub>2</sub> in the absence of H<sub>2</sub>, and a conversion of 70% was obtained at 200 °C. For the CO oxidation in the presence of H<sub>2</sub> over these catalysts, the oxidation of H<sub>2</sub> was favoured over CO due to H<sub>2</sub> spillover occurring at the active metal and support interface, resulting in the formation of interstitials catalysed by Ir. However, both catalysts showed promising activity for CO hydrogenation. Ir-ZrO<sub>2</sub> was more active, giving 99.9% CO conversions from 350 to 370 °C, with high selectivity towards CH<sub>4</sub> using minimal H<sub>2</sub> from the feed. Furthermore, results for the Ir-ZrO<sub>2</sub> catalyst showed that the superior activity compared to the Ir-TiO<sub>2</sub> catalyst was mainly due to the reducibility of the support and its interaction with the active metal. Controlling the isoelectric point during the synthesis allowed for a stronger interaction between Ir and the ZrO<sub>2</sub> support, which resulted in higher catalytic activity due to better metal dispersions, and higher CO chemisorption capacities than obtained for the Ir-TiO<sub>2</sub> catalyst. |
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