Kinetic hindrance during the initial oxidation of Pd(100) at ambient pressures

Abstract

The oxidation of the Pd(100) surface at oxygen pressures in the 10^-6 to 10^3 mbar range and temperatures up to 1000 K has been studied in-situ by surface x-ray diffraction (SXRD). The results provide direct structural information on the phases present in the surface region and on the kinetics of the oxide formation. Depending on the (T,p) environmental conditions we either observe a thin sqrt(5) x sqrt(5) R27 surface oxide or the growth of a rough, poorly ordered bulk oxide film of PdO predominantly with (001) orientation. By either comparison to the surface phase diagram from first-principles atomistic thermodynamics or by explicit time-resolved measurements we identify a strong kinetic hindrance to the bulk oxide formation even at temperatures as high as 675 K.

4 pages including 4 figures, Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.html

References in corpus (3)

• Composition, structure and stability of RuO_2(110) as a function of oxygen pressure
• The Pd(100)-(SQRT(5) x SQRT(5) R27^o)-O surface oxide revisited
• Why is a noble metal catalytically active? The role of the O-Ag interaction in the function of silver as an oxidation catalyst

Cited by in corpus (8)

• Ab initio atomistic thermodynamics and statistical mechanics of surface properties and functions
• First-principles statistical mechanics study of the stability of a sub-nanometer thin surface oxide in reactive environments: CO oxidation at Pd(100)
• CO oxidation at Pd(100): A first-principles constrained thermodynamics study
• In situ X-ray photoelectron spectroscopy of model catalysts: At the edge of the gap
• CO oxidation on Pd(100) at technologically relevant pressure conditions: A first-principles kinetic Monte Carlo study
• Multi-Lattice Kinetic Monte Carlo Simulations from First-Principles: Reduction of the Pd(100) Surface Oxide by CO
• CO oxidation on Pd(100) vs. PdO(sqrt5xsqrt5)R27^o: First-Principles Kinetic Phase Diagrams and Bistability Conditions
• First-principles statistical mechanics approach to step decoration at surfaces