The decomposition of formic acid proceeds via two principal reaction pathways: dehydration and dehydrogenation. Mechanisms and reaction ratios depend on the nature of the catalysts used. This work provides mechanistic insight into the decomposition of formic acid on Co(0001) and a highly stepped cobalt surface. The catalytic systems were studied in ultra-high vacuum by XPS and temperature programmed desorption. On both surfaces, an overall reaction (1) was observed:
2 HCOOH→H_2 O+CO+H_2+CO_2 (1)
The surfaces had differing reaction intermediates, reaction temperatures, and activation energies. On Co(0001), formate, carbon, and hydroxyl are intermediates and the reaction has an activation energy of 44.3 ± 0.6 kJ/mol, pre-exponential factor of 0.7 ± 0.05 mbar/s. On highly stepped cobalt, formate and formyl are intermediates and the reaction has an activation energy of 147.2 ± 2.0 kJ/mol and pre-exponential factor of 1011.3 ± 0.2 mbar/s. Desorption energies of observed species and mechanisms of observed reactions are reported.
A detailed description and proof of concept of a PM-IRRAS reactor designed for this thesis is also presented.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/32592 |
| Date | January 2015 |
| Creators | Sims, Jeffrey J. |
| Contributors | Giorgi, Javier |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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