Key role of CO coverage for chain growth in co-based Fischer–Tropsch synthesis
- Author
- Konstantijn Rommens (UGent) , Kasun Gunasooriya and Mark Saeys (UGent)
- Organization
- Project
- Abstract
- Fischer-Tropsch synthesis converts CO and H-2 to long-chain hydrocarbons. The reaction mechanism, a combination of C-O scission, C-C coupling, and hydrogenation steps, and the nature of the active sites remain intensely debated. In this work, we report a comprehensive, dual-site microkinetic model including more than 600 reversible reactions. Our model explicitly accounts for the high CO surface coverage under the reaction conditions by including a CO saturation coverage in the underlying DFT calculations. The model predictions match experimental kinetic observations with a methane selectivity of 18%, a chain growth probability of 0.83, a turnover frequency of 0.084 s(-1), and an activation energy of 107 kJ/mol. A degree of rate control analysis identifies 12 rate-controlling steps, highlighting the challenges in building compact kinetic models based on one or two rate controlling steps. In the dominant reaction mechanism, CO is activated both at B-5 step sites and at the terrace sites via H- and hydroxyl-assisted pathways. Chain growth occurs on the crowded terraces predominantly via CH coupling to alkylidine chains. While B-5 step sites facilitate CO activation, a small concentration of 5% is sufficient to establish a quasi-equilibrium CH coverage on the terraces and higher concentrations do not notably change the model predictions.
- Keywords
- catalysis, cobalt, Fischer-Tropsch synthesis, active site, microkinetics, coverage effects, TOTAL-ENERGY CALCULATIONS, FINDING SADDLE-POINTS, PRODUCT DISTRIBUTION, COBALT, MECHANISM, SIZE, CATALYST, SELECTIVITY, HYDROGENATION, ACTIVATION
Downloads
-
(...).pdf
- full text (Published version)
- |
- UGent only
- |
- |
- 5.80 MB
-
MKM FT saeys v9 003 .pdf
- full text (Accepted manuscript)
- |
- open access
- |
- |
- 1.99 MB
Citation
Please use this url to cite or link to this publication: http://hdl.handle.net/1854/LU-01JN3SDVRNZE8X9B30XVD1R8ME
- MLA
- Rommens, Konstantijn, et al. “Key Role of CO Coverage for Chain Growth in Co-Based Fischer–Tropsch Synthesis.” ACS CATALYSIS, vol. 14, no. 9, 2024, pp. 6696–709, doi:10.1021/acscatal.3c04844.
- APA
- Rommens, K., Gunasooriya, K., & Saeys, M. (2024). Key role of CO coverage for chain growth in co-based Fischer–Tropsch synthesis. ACS CATALYSIS, 14(9), 6696–6709. https://doi.org/10.1021/acscatal.3c04844
- Chicago author-date
- Rommens, Konstantijn, Kasun Gunasooriya, and Mark Saeys. 2024. “Key Role of CO Coverage for Chain Growth in Co-Based Fischer–Tropsch Synthesis.” ACS CATALYSIS 14 (9): 6696–6709. https://doi.org/10.1021/acscatal.3c04844.
- Chicago author-date (all authors)
- Rommens, Konstantijn, Kasun Gunasooriya, and Mark Saeys. 2024. “Key Role of CO Coverage for Chain Growth in Co-Based Fischer–Tropsch Synthesis.” ACS CATALYSIS 14 (9): 6696–6709. doi:10.1021/acscatal.3c04844.
- Vancouver
- 1.Rommens K, Gunasooriya K, Saeys M. Key role of CO coverage for chain growth in co-based Fischer–Tropsch synthesis. ACS CATALYSIS. 2024;14(9):6696–709.
- IEEE
- [1]K. Rommens, K. Gunasooriya, and M. Saeys, “Key role of CO coverage for chain growth in co-based Fischer–Tropsch synthesis,” ACS CATALYSIS, vol. 14, no. 9, pp. 6696–6709, 2024.
@article{01JN3SDVRNZE8X9B30XVD1R8ME,
abstract = {{Fischer-Tropsch synthesis converts CO and H-2 to long-chain hydrocarbons. The reaction mechanism, a combination of C-O scission, C-C coupling, and hydrogenation steps, and the nature of the active sites remain intensely debated. In this work, we report a comprehensive, dual-site microkinetic model including more than 600 reversible reactions. Our model explicitly accounts for the high CO surface coverage under the reaction conditions by including a CO saturation coverage in the underlying DFT calculations. The model predictions match experimental kinetic observations with a methane selectivity of 18%, a chain growth probability of 0.83, a turnover frequency of 0.084 s(-1), and an activation energy of 107 kJ/mol. A degree of rate control analysis identifies 12 rate-controlling steps, highlighting the challenges in building compact kinetic models based on one or two rate controlling steps. In the dominant reaction mechanism, CO is activated both at B-5 step sites and at the terrace sites via H- and hydroxyl-assisted pathways. Chain growth occurs on the crowded terraces predominantly via CH coupling to alkylidine chains. While B-5 step sites facilitate CO activation, a small concentration of 5% is sufficient to establish a quasi-equilibrium CH coverage on the terraces and higher concentrations do not notably change the model predictions.}},
author = {{Rommens, Konstantijn and Gunasooriya, Kasun and Saeys, Mark}},
issn = {{2155-5435}},
journal = {{ACS CATALYSIS}},
keywords = {{catalysis,cobalt,Fischer-Tropsch synthesis,active site,microkinetics,coverage effects,TOTAL-ENERGY CALCULATIONS,FINDING SADDLE-POINTS,PRODUCT DISTRIBUTION,COBALT,MECHANISM,SIZE,CATALYST,SELECTIVITY,HYDROGENATION,ACTIVATION}},
language = {{eng}},
number = {{9}},
pages = {{6696--6709}},
title = {{Key role of CO coverage for chain growth in co-based Fischer–Tropsch synthesis}},
url = {{http://doi.org/10.1021/acscatal.3c04844}},
volume = {{14}},
year = {{2024}},
}
- Altmetric
- View in Altmetric
- Web of Science
- Times cited: