Abstract
Dissociation of CO on a Co(0001) surface is explored in the context of Fischer-Tropsch synthesis on cobalt catalysts. Experiments show that CO dissociation can occur on defect sites around 330 K, with an estimated barrier between 90 and 104 kJ mol- 1. Despite the ease of CO dissociation on defect sites, extensive carbon deposition onto the cobalt surface up to 0.33 ML requires a combination of high surface temperature and a relatively high CO pressure. Experimental data on the CO oxidation reaction indicate a high reaction barrier for the CO + O reaction, and it is argued that, due to the rather strong Co-O bond, (i) oxygen removal is the rate-limiting step during surface carbidization and (ii) in the context of Fischer-Tropsch synthesis, removal of surface oxygen rather than CO bond scission might be limiting the overall reaction rate.
| Original language | English |
|---|---|
| Pages (from-to) | 60-66 |
| Number of pages | 7 |
| Journal | Surface Science |
| Volume | 648 |
| DOIs | |
| Publication status | Published - Jun 2016 |
Funding
The authors thank Prof. J.N. Andersen for beamtime at beamline I311 (MAX-lab, Lund). ELETTRA is acknowledged for beamtime at the SuperESCA beamline. We thank A.C. Kizilkaya for the hydrogen desorption spectra showing the passivation of defects by a CO treatment. The help of the technical staff at ELETTRA (Trieste, Italy) and at TU/e Eindhoven is also greatly appreciated. J.A. van den Berg, M.A. Petersen and I.M. Ciobîcă are acknowledged for helpful discussions. CJW acknowledges his present employer, Syngaschem BV, for allowing the time to work on this article. Appendix A
Keywords
- CO dissociation
- Co(0001)
- Fischer-Tropsch synthesis
- Oxygen reduction
- Surface carbiding