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Coexisting multi-states in catalytic hydrogen oxidation on rhodium
P Winkler1, J Zeininger1, M Raab1
1Institute of Materials Chemistry, TU Wien, Getreidemarkt 9, 1060, Vienna, Austria.
This study reveals multiple coexisting states during catalytic hydrogen oxidation on rhodium surfaces. These findings demonstrate the possibility of multi-state catalysis and offer insights into surface reactions.
Area of Science:
- Surface science
- Catalysis
- Chemical kinetics
Background:
- Polycrystalline rhodium (Rh) is crucial for catalytic hydrogen oxidation.
- Understanding surface states is key to optimizing catalytic processes.
Purpose of the Study:
- To investigate the coexistence of different catalytic states on a rhodium surface.
- To explore the influence of surface structure on catalytic activity.
Main Methods:
- Scanning photoelectron microscopy (SPEM) for spatially resolved measurements.
- X-ray photoemission spectroscopy (XPS) to analyze surface composition.
- Mean-field micro-kinetic modeling to support experimental findings.
Main Results:
- Observed four distinct coexisting states (active, inactive, and oscillating) on adjacent rhodium domains under identical conditions.
- Identified subsurface oxygen formation and depletion as key factors influencing these states.
- Demonstrated the general possibility of multi-state behavior in catalytic reactions.
Conclusions:
- Catalytic reactions can exhibit multiple stable or dynamic states simultaneously.
- Surface structure and subsurface species significantly impact catalytic behavior.
- The study raises questions about self-organization in heterogeneous systems with permeable boundaries.
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