Impurity effects on oxygen reduction electrocatalysis at platinum ultramicroelectrodes

A critical assessment

Daniel Alberto Scherson, Yuriy V. Tolmachev

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Impurity effects associated with an increase in the rate of mass transport induced by a decrease in the size of electrodes have been examined with emphasis on species capable of undergoing irreversible adsorption. Calculations show that for hemispherical ultramicroelectrodes 50 nm in radius, the flux of a solution-phase contaminant, such as a small organic molecule, present at ppb levels, is large enough to reach saturation coverage over times on the order of seconds. In the case of dioxygen reduction on Pt in aqueous electrolytes, such adsorbed species are believed to be responsible for marked changes in the mechanism, promoting a two-electron over a four-electrode reduction pathway. Such aspects must be considered in the analysis of results obtained with Pt ultramicroelectrodes, either as single particles or in dilute arrays.

Original languageEnglish
JournalElectrochemical and Solid-State Letters
Volume13
Issue number2
DOIs
Publication statusPublished - 2010 Jan 21
Externally publishedYes

Fingerprint

Electrocatalysis
Platinum
platinum
Impurities
Oxygen
impurities
Electrodes
electrodes
oxygen
Electrolytes
contaminants
Mass transfer
electrolytes
Fluxes
saturation
Adsorption
Molecules
adsorption
radii
Electrons

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Electrochemistry
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering
  • Materials Science(all)

Cite this

@article{eb56e1f45fc64889b98885e3258e62e4,
title = "Impurity effects on oxygen reduction electrocatalysis at platinum ultramicroelectrodes: A critical assessment",
abstract = "Impurity effects associated with an increase in the rate of mass transport induced by a decrease in the size of electrodes have been examined with emphasis on species capable of undergoing irreversible adsorption. Calculations show that for hemispherical ultramicroelectrodes 50 nm in radius, the flux of a solution-phase contaminant, such as a small organic molecule, present at ppb levels, is large enough to reach saturation coverage over times on the order of seconds. In the case of dioxygen reduction on Pt in aqueous electrolytes, such adsorbed species are believed to be responsible for marked changes in the mechanism, promoting a two-electron over a four-electrode reduction pathway. Such aspects must be considered in the analysis of results obtained with Pt ultramicroelectrodes, either as single particles or in dilute arrays.",
author = "Scherson, {Daniel Alberto} and Tolmachev, {Yuriy V.}",
year = "2010",
month = "1",
day = "21",
doi = "10.1149/1.3264089",
language = "English",
volume = "13",
journal = "Electrochemical and Solid-State Letters",
issn = "1099-0062",
publisher = "Electrochemical Society, Inc.",
number = "2",

}

TY - JOUR

T1 - Impurity effects on oxygen reduction electrocatalysis at platinum ultramicroelectrodes

T2 - A critical assessment

AU - Scherson, Daniel Alberto

AU - Tolmachev, Yuriy V.

PY - 2010/1/21

Y1 - 2010/1/21

N2 - Impurity effects associated with an increase in the rate of mass transport induced by a decrease in the size of electrodes have been examined with emphasis on species capable of undergoing irreversible adsorption. Calculations show that for hemispherical ultramicroelectrodes 50 nm in radius, the flux of a solution-phase contaminant, such as a small organic molecule, present at ppb levels, is large enough to reach saturation coverage over times on the order of seconds. In the case of dioxygen reduction on Pt in aqueous electrolytes, such adsorbed species are believed to be responsible for marked changes in the mechanism, promoting a two-electron over a four-electrode reduction pathway. Such aspects must be considered in the analysis of results obtained with Pt ultramicroelectrodes, either as single particles or in dilute arrays.

AB - Impurity effects associated with an increase in the rate of mass transport induced by a decrease in the size of electrodes have been examined with emphasis on species capable of undergoing irreversible adsorption. Calculations show that for hemispherical ultramicroelectrodes 50 nm in radius, the flux of a solution-phase contaminant, such as a small organic molecule, present at ppb levels, is large enough to reach saturation coverage over times on the order of seconds. In the case of dioxygen reduction on Pt in aqueous electrolytes, such adsorbed species are believed to be responsible for marked changes in the mechanism, promoting a two-electron over a four-electrode reduction pathway. Such aspects must be considered in the analysis of results obtained with Pt ultramicroelectrodes, either as single particles or in dilute arrays.

UR - http://www.scopus.com/inward/record.url?scp=74249123321&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=74249123321&partnerID=8YFLogxK

U2 - 10.1149/1.3264089

DO - 10.1149/1.3264089

M3 - Article

VL - 13

JO - Electrochemical and Solid-State Letters

JF - Electrochemical and Solid-State Letters

SN - 1099-0062

IS - 2

ER -