Surface-structure libraries: multifrequential oscillations in catalytic hydrogen oxidation on rhodium
Journal article, 2019

Multifrequential oscillating spatiotemporal patterns in the catalytic hydrogen oxidation on rhodium have been observed in situ in the 10 -6 mbar pressure range using photoemission electron microscopy. The effect is manifested by periodic chemical waves, which travel over the polycrystalline Rh surface and change their oscillation frequency while crossing boundaries between different Rh(hkl) domains. Each crystallographically specific μm-sized Rh(hkl) domain exhibits an individual wave pattern and oscillation frequency, despite the global diffusional coupling of the surface reaction, altogether creating a structure library. This unique reaction behavior is attributed to the ability of stepped surfaces of high-Miller-index domains to facilitate the formation of subsurface oxygen, serving as a feedback mechanism of kinetic oscillations. Formation of a network of subsurface oxygen as a result of colliding reaction fronts was observed in situ. Microkinetic model analysis was used to rationalize the observed effects and to reveal the relation between the barriers for surface oxidation and oscillation frequency. Structural limits of the oscillations, the existence range of oscillations, as well as the effect of varying hydrogen pressure are demonstrated.


Y. Suchorski

Vienna University of Technology

Martin Datler

Vienna University of Technology

Ivan Bespalov

Vienna University of Technology

Johannes Zeininger

Vienna University of Technology

M. Stoger-Pollach

Vienna University of Technology

J. Bernardi

Vienna University of Technology

Henrik Grönbeck

Chalmers, Physics, Chemical Physics

G. Rupprechter

Vienna University of Technology

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 123 7 4217-4227

Subject Categories

Inorganic Chemistry

Materials Chemistry

Other Chemistry Topics



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