Oxygen adsorption on the Al₉Co₂(001) surface: first-principles and STM study
S Alarcón Villaseca1, L N Serkovic Loli, J Ledieu
1Institut Jean Lamour, UMR 7198 (CNRS Université de Lorraine), Parc de Saurupt, F-54011 Nancy Cedex, France.
Summary
Atomic oxygen preferentially adsorbs on Al9Co2(001) surfaces at bridge sites. This adsorption involves covalent Al-O bonding and influences surface layer relaxation, with subsurface cobalt atoms playing a key role.
Area of Science:
- Materials Science
- Surface Science
- Computational Chemistry
Background:
- Understanding atomic oxygen adsorption on intermetallic surfaces is crucial for catalysis and corrosion resistance.
- The Al9Co2 alloy presents a unique surface structure with exposed aluminum and cobalt atoms.
Purpose of the Study:
- To investigate the preferential adsorption sites and electronic structure of atomic oxygen on the Al9Co2(001) surface.
- To elucidate the nature of the aluminum-oxygen (Al-O) bond and the influence of subsurface cobalt on adsorption energetics.
Main Methods:
- First-principle calculations (e.g., Density Functional Theory) were employed to determine adsorption energies and electronic structures.
- Scanning Tunneling Microscopy (STM) measurements were used to validate theoretical predictions and observe surface morphology.
Main Results:
- The most favorable adsorption site for atomic oxygen was identified as a 'bridge' site between aluminum clusters on the (001) surface.
- Al-O bonding exhibits covalent character with s-p hybridization, and significant atomic relaxations occur in the topmost surface layer.
- Subsurface cobalt atoms were found to significantly impact adsorption energies.
Conclusions:
- Atomic oxygen adsorption on Al9Co2(001) is well-described by theoretical calculations and experimental STM observations.
- The study highlights the importance of surface structure, bonding characteristics, and subsurface composition in determining oxygen adsorption behavior on intermetallic compounds.
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