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Controlling O coverage and stability by alloying Au and Ag
Matthew M Montemore1, Ekin D Cubuk2, J Eric Klobas3
1Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA and School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
Physical Chemistry Chemical Physics : PCCP
|October 11, 2016
Summary
Alloying gold (Au) into silver (Ag) surfaces controls oxygen
Area of Science:
- Surface science
- Catalysis
- Materials science
Background:
- Gold (Au) and silver (Ag) are effective selective oxidation catalysts.
- Controlling oxygen's surface state is crucial for catalytic performance.
Purpose of the Study:
- Investigate how alloying Au into Ag(110) affects oxygen adsorption and dissociation.
- Determine the impact of Au concentration on oxygen coverage and stability.
Main Methods:
- Density functional theory (DFT) calculations
- Monte Carlo simulations
- Temperature programmed desorption
Main Results:
- Au in the second layer inhibits O2 dissociation by direct repulsion.
- Oxygen uptake decreases linearly with increasing Au concentration, ceasing above 50% Au.
- Oxygen stability decreases with Au concentration above 18%.
Conclusions:
- Alloying Au and Ag allows tuning of oxygen coverage and stability on catalytic surfaces.
- This control over oxygen species can be achieved independently.
- Surface oxygen state manipulation impacts catalytic reactivity, demonstrated by CO2 oxidation.
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