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CO2 Utilization in Catalytic Dehydrogenation: Enhancing Selectivity and Reducing Coking

This study explores the role of CO2 as a soft oxidant in oxidative dehydrogenation (ODH) processes, significantly impacting the dehydrogenation pathway. By using CO2, we can alleviate chemical equilibrium issues and suppress coking through decoking reactions, ultimately yielding hydrogen and carbon monoxide. The investigation employs various catalysts, comparing their effectiveness in the presence of CO2 versus their absence. Key findings indicate that CO2 not only maintains lattice oxygen in catalysts but also improves selectivity in hydrocarbon conversion, showcasing its potential in sustainable catalysis.

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CO2 Utilization in Catalytic Dehydrogenation: Enhancing Selectivity and Reducing Coking

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  1. Literature Report FengJiang 2013.5.10

  2. high-energy costs Dehydrogenation coke formation ODH with O2 Low selectivity ODH with CO2 soft oxidant CO2

  3. Carbon dioxide utilization as a soft oxidant and promoter in catalysis Mohd Bismillah Ansari and Sang-Eon Park* Energy Environ. Sci., 2012, 5, 9419-9437

  4. Role of CO2 form CO and oxygen species and change the dehydrogenation pathway in an oxidative manner • alleviate the chemical equilibrium in ODH • H2 +CO2 → CO + H2O • suppress coking via a decoking reaction • C+CO2→ 2CO

  5. acid–base properties： Without CO2 With CO2 4

  6. surface/lattice oxygen species： R–CH2CH3 +MOx → R–CH=CH2 +H2O+MOx-1 MOx-1+CO2 → MOx+ CO CO2 maintains the lattice oxygen of the catalyst

  7. 18O isotope experiment M16Ox+C18O2→M18O16Ox-1+ C18O16O M16Ox+C18O2→M18O216Ox-2+ C16O2 Nihao MS record: C18O2,m/z 48; C18O16O,m/z 46; C16O2, m/z 44 MOx-1 +CO2 → MOx+ CO really exists

  8. Redox mechanism √ Chromium, and Vanadium oxide-based catalysts × Gallium, Indium oxide-based catalysts

  9. (1) • (2) • (3) • (4) B.J. Xu, B. Zheng, W.M. Hua, Y.H. Yue, Z. Gao, J. Catal. 239 (2006) 470-477.

  10. (5) With CO2 • (6) • (6)>>(5) B.J. Xu, B. Zheng, W.M. Hua, Y.H. Yue, Z. Gao, J. Catal. 239 (2006) 470-477.

  11. Thank You !

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