Predicting the segregation profile of the Pt25Rh75(100) surface from first-principles.
P Welker1, O Wieckhorst, T C Kerscher
1Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstrasse 7, 91058 Erlangen, Germany.
Summary
This study investigates platinum-rhodium surface segregation using advanced computational methods. Calculations confirm experimental findings of platinum enrichment in the top layer of Pt(25)Rh(75) surfaces.
Area of Science:
- Materials Science
- Surface Science
- Computational Chemistry
Background:
- Surface segregation is crucial for understanding alloy properties.
- Platinum-Rhodium alloys are important in catalysis and materials applications.
- Predicting segregation behavior is key for alloy design.
Purpose of the Study:
- To investigate the surface segregation profile of the Platinum-Rhodium (Pt-Rh) (100) surface.
- To predict the most stable atomic configurations and temperature-dependent concentration profiles.
- To validate computational predictions against experimental observations.
Main Methods:
- Density Functional Theory (DFT) calculations.
- Cluster-expansion (CE) method for modeling interactions.
- Grand-canonical Monte Carlo (GCMC) simulations for temperature effects.
Main Results:
- A stability diagram for surface layers was constructed.
- The most stable atomic configurations were predicted for given layer concentrations.
- Calculations accurately reproduced the experimental Pt enrichment in the top layer and depletion in the second layer of Pt(25)Rh(75).
Conclusions:
- The combination of DFT, CE, and GCMC is effective for studying surface segregation.
- Computational predictions align well with experimental data for Pt-Rh alloys.
- Understanding segregation profiles aids in designing alloys with desired surface properties.
