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Peroxide electroreduction on bi-modified Au surfaces: vibrational spectroscopy and density functional calculations
1Department of Chemistry and Fredrick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Journal of the American Chemical Society
|June 5, 2003
Summary
The electroreduction of peroxide on bismuth-modified gold surfaces is clarified. Bismuth-hydroxyl species are key intermediates in peroxide electroreduction, with activity dependent on bismuth adatom spacing.
Area of Science:
- Electrochemistry
- Surface Science
- Computational Chemistry
Background:
- Understanding peroxide electroreduction is crucial for various electrochemical applications.
- Bismuth modification of electrode surfaces is explored for catalytic activity.
- The role of specific surface species in reaction mechanisms requires detailed investigation.
Purpose of the Study:
- To elucidate the mechanism of peroxide electroreduction on bismuth-submonolayer-modified Au(111) surfaces.
- To investigate the influence of bismuth coverage and adatom spacing on catalytic activity.
- To identify key intermediate species involved in the electroreduction process.
Main Methods:
- Surface-enhanced Raman scattering (SERS) measurements were employed to identify surface species.
- Density functional theory (DFT) calculations were performed to model reaction pathways and energetics.
- Electrochemical experiments were conducted on Au(111) surfaces modified with varying bismuth coverages.
Main Results:
- SERS spectroscopy detected bismuth-hydroxyl (Bi-OH) and bismuth-oxide (Bi-O) species at potentials relevant to peroxide reduction.
- DFT calculations revealed that peroxide is unstable relative to Bi-OH on the catalytically active (2x2) Bi/Au(111) surface.
- Catalytic activity was observed for submonolayer bismuth coverages, with inactive behavior for a full bismuth monolayer, correlating with adatom spacing.
Conclusions:
- The study indicates that bismuth-hydroxyl (M-OH) species play a critical role in the electroreduction of peroxide.
- The catalytic activity is highly dependent on the specific configuration and spacing of bismuth adatoms on the Au(111) surface.
- These findings provide fundamental insights into the mechanism of peroxide electroreduction on modified electrode surfaces.
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