Oxidation of palladium on Au(111) and ZnO(0001) supports [electronic resource].
- Washington, D.C. : United States. Dept. of Energy. Office of Basic Energy Sciences, 2014.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- Article numbers 154,702 : digital, PDF file
- Additional Creators:
- Brookhaven National Laboratory
United States. Department of Energy. Office of Basic Energy Sciences
United States. Department of Energy. Office of Scientific and Technical Information
- The oxidation of supported Pd-deposits on Au(111) and ZnO(0001) single crystals has been studied by x- ray photoemission spectroscopy (XPS). Oxidation has been carried out <i>ex-situ</i> in a high-pressure cell with subsequent vacuum-transfer and characterization by XPS in ultrahigh vacuum (UHV), as well as using <i>in-situ</i> characterization by synchrotron based near-ambient pressure XPS. On Au(111) alloying of Pd with the substrate competes with oxidation and only sufficiently thick Pd films have been found to oxidize. For Pd on ZnO the oxidation conditions depend on the amount of deposited Pd. Thicker Pd deposits behave similar to bulk Pd, while thinner films oxidize already at lower temperatures. Interestingly, for very small amounts of Pd, <i>in-situ</i> XPS shows full oxidation at room temperature and at less than 0.6 mbar O2 pressure. This indicates a lowering of the kinetic barriers for oxidation of very small supported Pd-clusters. The formed oxide is, however, not stable in UHV and a slow reduction is observed. The instability of this oxide indicates that the Pd-oxide formed at the interface to ZnO may have different chemical properties compared to bulk PdO or surface oxides on Pd.
- Published through SciTech Connect.
Journal of Chemical Physics 141 15 ISSN 0021-9606; JCPSA6 AM
Lallo, J.; Tenney, S.; Kramer, A.; Sutter, P.; Batzill, M.
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