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Published on: December 4, 2014
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The (111) surface of NaAu2: structure, composition, and stability
Emma J Kwolek1, Roland Widmer, Oliver Gröning
1Department of Chemistry and ∥Department of Materials Science & Engineering, Iowa State University , Ames, Iowa 50011, United States.
Inorganic Chemistry
|December 18, 2014
Summary
Preparing the sodium-gold (NaAu(2)) surface for catalysis is challenging due to sodium loss. Optimized conditions reveal a bulk-terminated structure with disordered surface mesas.
Area of Science:
- Surface Science
- Materials Science
- Catalysis
Background:
- The (111) surface of NaAu(2) serves as a model for catalytically active NaAu(2) powders.
- Understanding surface properties is crucial for optimizing catalytic applications.
Purpose of the Study:
- To prepare and characterize the (111) surface of single-crystal NaAu(2).
- To investigate the effects of preparation techniques on surface structure and composition.
Main Methods:
- Ultrahigh vacuum preparation involving ion bombardment and thermal annealing.
- Surface characterization using electron diffraction and scanning tunneling microscopy (STM).
Main Results:
- Preparation methods lead to sodium (Na) loss and conversion to crystalline gold.
- The bulk NaAu(2) can partially repopulate the surface, but Na depletion is a challenge.
- Under optimized conditions, STM revealed mesa-like features with disordered surface layers.
Conclusions:
- Achieving a stable, well-defined NaAu(2) surface requires minimizing Na depletion.
- The observed mesa structures suggest complex surface reconstruction under experimental conditions.
- Further research is needed to control surface disorder for enhanced catalytic activity.
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