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Quantitative DEMS study of ethanol oxidation: effect of surface structure and Sn surface modification
Ehab Mostafa1, Abd-El-Aziz A Abd-El-Latif, Richard Ilsley
1Institute of Physical and Theoretical Chemistry, University of Bonn, Germany.
Physical Chemistry Chemical Physics : PCCP
|October 31, 2012
Summary
Ethanol electrooxidation on platinum electrodes primarily yields acetaldehyde. Tin modification of Pt(311) shifted onset potential but did not enhance CO2 production, with acetaldehyde and acetic acid remaining main products.
Area of Science:
- Electrochemistry
- Surface Science
- Analytical Chemistry
Background:
- Ethanol electrooxidation is crucial for fuel cells and chemical synthesis.
- Understanding reaction pathways and product selectivity on different platinum surfaces is key.
- Volatile product analysis using advanced techniques is essential for mechanistic studies.
Purpose of the Study:
- To investigate the volatile products of ethanol electrooxidation on various platinum electrodes.
- To analyze the effect of electrode surface structure (polycrystalline, specific facets, roughened) and tin modification.
- To quantify acetaldehyde and carbon dioxide formation using on-line differential electrochemical mass spectroscopy (DEMS).
Main Methods:
- Differential electrochemical mass spectroscopy (DEMS) with a dual thin layer flow through cell.
- Potentiostatic measurements to determine oxidation onset potentials.
- Analysis of ethanol and i-propanol electrooxidation on polycrystalline Pt, Pt(111), Pt(311), and Sn-modified Pt electrodes.
Main Results:
- Polycrystalline Pt primarily produced acetaldehyde; further oxidation to acetic acid was negligible.
- Pt(111) predominantly yielded acetaldehyde, while Pt(311) produced both acetaldehyde and acetic acid.
- Tin modification inhibited ethanol oxidation on Pt(111) and shifted the onset potential negatively on Pt(311) without increasing CO2 production.
Conclusions:
- Ethanol electrooxidation pathways are highly dependent on the platinum electrode's surface structure.
- Tin modification influences the electrocatalytic activity and product distribution of ethanol oxidation.
- DEMS is effective for semi-quantitative analysis of volatile products in ethanol electrooxidation studies.
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