Carbon in palladium catalysts: A metastable carbide
- Author(s)
- Nicola Seriani, Florian Mittendorfer, Georg Kresse
- Abstract
The catalytic activity of palladium toward selective hydrogenation of hydrocarbons depends on the partial pressure of hydrogen. It has been suggested that the reaction proceeds selectively toward partial hydrogenation only when a carbon-rich film is present at the metal surface. On the basis of first-principles simulations, we show that carbon can dissolve into the metal because graphite formation is delayed by the large critical nucleus necessary for graphite nucleation. A bulk carbide Pd6C with a hexagonal six-layer fcc-like supercell forms. The structure is characterized by core level shifts of 0.66-0.70 eV in the core states of Pd, in agreement with experimental x-ray photoemission spectra. Moreover, this phase traps bulk-dissolved hydrogen, suppressing the total hydrogenation reaction channel and fostering partial hydrogenation.
- Organisation(s)
- Computational Materials Physics
- Journal
- Journal of Chemical Physics
- Volume
- 132
- No. of pages
- 8
- ISSN
- 0021-9606
- DOI
- https://doi.org/10.1063/1.3290813
- Publication date
- 2010
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103009 Solid state physics, 103015 Condensed matter, 103025 Quantum mechanics, 103036 Theoretical physics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/ac1e7c45-0385-46ac-8b43-156cf1f2ecc2