| Autor: |
Hosono, Yukiko, Saito, Hikaru, Higo, Takuma, Watanabe, Kosuke, Ito, Kazuharu, Tsuneki, Hideaki, Maeda, Shun, Hashimoto, Kunihide, Sekine, Yasushi |
| Zdroj: |
The Journal of Physical Chemistry - Part C; June 2021, Vol. 125 Issue: 21 p11411-11418, 8p |
| Abstrakt: |
Introducing a catalyst for dehydrogenation of ethane (EDH) for steam cracking represents a promising solution with high feasibility to realize efficient ethylene production. We investigated EDH over transition-metal-doped CeO2catalysts at 873 K in the presence of steam. Ce0.8Co0.2O2exhibited high EDH activity and selectivity to ethylene (ca. 95%). In the absence of H2O, the catalytic activity dropped rapidly, indicating the promotive effect of H2O on ethylene formation. Catalytic experiments with water isotopes (D2O and H218O) demonstrated that EDH over Ce0.8Co0.2O2proceeds through the Mars–van Krevelen (MvK) mechanism in which the reactive lattice oxygen in Ce0.8Co0.2O2contributes to EDH. The consumed lattice oxygen was subsequently regenerated with H2O. X-ray diffraction and in situX-ray absorption fine structure spectroscopy revealed that cobalt species were mainly present as CoO under EDH conditions and that redox between Co2+and Co0proceeded concomitantly with EDH. In contrast with Ce0.8Co0.2O2, no contribution of the lattice oxygen of CoO to EDH was verified in the case of CoO supported on α-Al2O3, which exhibited lower activity than Ce0.8Co0.2O2. Therefore, Co–CeO2interactions are expected to play a crucially important role in controlling the characteristics of the reactive lattice oxygen suitable for EDH viathe MvK mechanism. |
| Databáze: |
Supplemental Index |
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