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Oxygen and silver clusters: transition from chemisorption to oxidation
M Schmidt1, A Masson, C Bréchignac
1Laboratoire Aimé Cotton, CNRS, Bâtiment 505, Campus d'Orsay, 91405 Orsay Cedex, France.
Physical Review Letters
|December 20, 2003
Summary
Investigating nitrogen and oxygen adsorption on silver particles reveals surface structure dictates physisorption, while electronic configuration governs oxygen chemisorption and subsequent oxidation.
Area of Science:
- Surface Science
- Materials Chemistry
- Catalysis
Background:
- Understanding gas-surface interactions is crucial for catalysis and materials science.
- Silver nanoparticles exhibit unique electronic and structural properties influencing adsorption behavior.
Purpose of the Study:
- To investigate the physisorption and chemisorption of molecular nitrogen (N2) and oxygen (O2) on small silver particles.
- To elucidate the roles of surface structure and electronic configuration in these adsorption processes.
Main Methods:
- Adsorption probability measurements of N2 and O2 on silver particles.
- Variable temperature studies to differentiate adsorption and reaction pathways.
Main Results:
- Nitrogen physisorption is primarily determined by the silver particle surface structure.
- Oxygen chemisorption at 77 K involves electron transfer to the silver cluster.
- At temperatures above 105 K, oxygen chemisorption transitions to oxidation, leading to O2 dissociation.
Conclusions:
- Surface structure and electronic properties of silver nanoparticles significantly influence gas adsorption.
- Distinct mechanisms govern N2 physisorption and O2 chemisorption/oxidation on silver.
- The findings provide insights into the reactivity of silver surfaces with small molecules.