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Electrocatalytic oxidation of ethanol on Pt, Pt-Ru and Pt-Sn nanoparticles in polymer electrolyte membrane fuel cell—Role of oxygen permeation

Paper ID Volume ID Publish Year Pages File Format Full-Text
46402 46439 2012 6 PDF Available
Title
Electrocatalytic oxidation of ethanol on Pt, Pt-Ru and Pt-Sn nanoparticles in polymer electrolyte membrane fuel cell—Role of oxygen permeation
Abstract

We have recently shown that in low temperature, polymer-electrolyte membrane direct ethanol fuel cells oxygen permeating from cathode is able to chemically oxidize ethanol at the anode surface [A. Jablonski, P.J. Kulesza, A. Lewera, Journal of Power Sources 196 (2011) 4714–4718]. Such process is responsible for significant amounts of acetaldehyde and acetic acid present at anode outlet, which are not related to the flow of electric current in external circuit. Here, for the first time, we report unbiased distribution of products of ethanol electrooxidation on Pt, Pt-Ru and Pt-Sn as a function of fuel cell voltage (under load) and temperature. We show here that for Pt anode and for cell voltage above 300 mV oxidation of ethanol to acetic acid does not occur as a result of electric current flow, but it is caused exclusively by chemical reaction between ethanol and oxygen permeating from cathode. This explains the obvious contradiction, which can be found in scientific literature regarding ethanol electrooxidation on Pt. Namely acetic acid is not observed in spectroelectrochemical, ex situ experiments in conditions comparable to working direct ethanol fuel cell, where it is detected in case of in situ, fuel cell experiments.Relation between unbiased distribution of products and anode catalyst's type, cell voltage, cell discharge current and temperature is also discussed. Oxygen permeation via Nafion 117 at 80 °C expressed in unit of electric current has been estimated to be at least 2.5–3.5 mA/cm2.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Effects of oxygen permeation in direct ethanol fuel cell has been investigated. ► Oxygen permeating from cathode side is able to parasitically oxidize ethanol. ► Acetic acid is produced on Pt surface exclusively due to oxygen permeation. ► Oxygen permeation can be held liable for the discrepancy observed in literature. ► Oxygen permeates thru Nafion 117 at least at 2.5–3.5 mA/cm2 rate.

Keywords
Fuel cells; Oxygen permeation; Ethanol electrooxidation; Platinum; Acetaldehyde; Acetic acid; Gas chromatography
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Electrocatalytic oxidation of ethanol on Pt, Pt-Ru and Pt-Sn nanoparticles in polymer electrolyte membrane fuel cell—Role of oxygen permeation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volumes 115–116, 5 April 2012, Pages 25–30
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us