DFT study of the thermodynamic stability of Pd-Pt bulk oxide phases
- Author(s)
- Arezoo Dianat, Nicola Seriani, Manfred Bobeth, Wolfgang Pompe, Lucio Colombi Ciacchi
- Abstract
The catalytic combustion activity of PdPt bimetallic catalysts is
governed by oxide phases which form under oxygen-rich operation
conditions. We investigate the thermodynamic stability of mixed PdxPt1−xOy phases with the crystal structures of PdO, PtO2, and Pt3O4
within an ab initio thermodynamics framework based on
density-functional theory calculations. Our results suggest a complex
mixing−demixing behavior of the Pd−Pt−O system upon variations of
temperature and oxygen partial pressure. At atmospheric pressure mixed
oxides are predicted to be stable only at temperatures below 400−500 K,
whereby the presence of Pd4+ ions is stabilized with increasing Pt amount in a PdxPt1−xO2 phase. At intermediate temperatures a mixture of phases becomes stable where PdO coexists with PtO2 or Pt3O4.
At high temperatures the oxides decompose directly to form PdPt alloys,
except for Pd-rich systems, where PdO and metallic Pt coexist within a
small temperature window.
- Organisation(s)
- Computational Materials Physics
- External organisation(s)
- Fraunhofer-Institut für Werkstoffmechanik IWM, Karlsruher Institut für Technologie, Technische Universität Dresden
- Journal
- The Journal of Physical Chemistry Part C (Nanomaterials and Interfaces)
- Volume
- 112
- Pages
- 13623–13628
- No. of pages
- 6
- ISSN
- 1932-7447
- DOI
- https://doi.org/10.1021/jp8035742
- Publication date
- 2008
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103018 Materials physics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/4790eedd-f6bb-45d1-abd4-80b88b506d42