H2 reduction of surface oxides on Pd-based membrane model systems – The case of Pd(100) and Pd75Ag25(100)
| Autor: | Sara Blomberg, Edvin Lundgren, L. E. Walle, Anne Borg, Mari Helene Farstad, V. R. Fernandes, Johan Gustafson, Hilde J. Venvik |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Hydrogen
Kinetics Analytical chemistry General Physics and Astronomy chemistry.chemical_element Surfaces and Interfaces General Chemistry Condensed Matter Physics Electron spectroscopy Oxygen Chemical reaction Surfaces Coatings and Films Membrane X-ray photoelectron spectroscopy chemistry Spectroscopy |
| Zdroj: | Applied Surface Science. 313:794-803 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/j.apsusc.2014.06.077 |
| Popis: | Reduction of the (root 5 x root 5)R27 degrees surface oxide on Pd(1 0 0) and Pd75Ag25(1 0 0) surfaces by H-2 has been studied using high-resolution photoelectron spectroscopy in situ at H-2 pressures 5 x 10(-9) mbar and 5 x 10(-8) mbar and selected temperatures in the range 30 degrees C to 170 degrees C. The reduction is slower on Pd75Ag25(1 0 0) compared to Pd(1 0 0) for all temperatures and pressures investigated. For Pd(1 0 0), the surface oxide reduction rate is rather independent of temperature, while for Pd75Ag25(1 0 0) a nonmonotonic variation is observed. As indicated by kinetic analysis, the complex reduction behavior is not well described by Avrami kinetics. Oxygen spillover effects contribute to this picture for Pd(1 0 0), while surface compositional effects appear to dominate the performance for Pd75Ag25(1 0 0). These findings may have implications for understanding the oxidation, reduction and hydrogen transport properties of Pd-Ag membranes. (C) 2014 Elsevier B.V. All rights reserved. (Less) |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect