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Title: Oxygen Reduction Reaction on Pt(111): Effects of Bromide

Abstract

Using the rotating ring-disk technique (RRDE) the oxygenreduction reaction (orr) was studied on the Pt(111) surface in thepresence of Br- anions. We found that the orr at the Pt(111) Bradinterface is always accompanied quantitatively by H2O2 oxidation currentson the ring electrode, implying that in the presence of Br- anions theorr does not proceed entirely through the 4e- reduction pathway, as inthe Br--free solution. We propose that strongly adsorbed Br- cansimultaneously suppress both the adsorption of the O2 molecule and theformation of pairs of platinum sites needed for the breaking of the O-Obond. Besides elucidating the effects of Brad, these studies also shedsome light on the role of OHad on the kinetics of the orr on the Pt(111)surface in solution free of Br anions. We have developed a theoreticalmodel and from simulations of I-E curves we propose two modes of actionof the OHad state on the kinetics of the orr on the Pt(111) surface: (i)OHad can block the adsorption of O2 on active platinum sites, i.e. theycompete for the same sites, and (ii) OHad can alter the adsorption energyof intermediates which are formed during the orr on the bare Pt sitesadjacent to the OHad.

Authors:
; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE Assistant Secretary for Energy Efficiency andRenewable Energy
OSTI Identifier:
895784
Report Number(s):
LBNL-42112
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Journal of Electroanalytical Chemistry
Additional Journal Information:
Journal Volume: 467; Journal Issue: 1; Related Information: Journal Publication Date: 06/07/1999
Country of Publication:
United States
Language:
English

Citation Formats

Markovic, N M, Gasteiger, H A, Grgur, B N, and Ross, Jr, P N. Oxygen Reduction Reaction on Pt(111): Effects of Bromide. United States: N. p., 1998. Web.
Markovic, N M, Gasteiger, H A, Grgur, B N, & Ross, Jr, P N. Oxygen Reduction Reaction on Pt(111): Effects of Bromide. United States.
Markovic, N M, Gasteiger, H A, Grgur, B N, and Ross, Jr, P N. Sat . "Oxygen Reduction Reaction on Pt(111): Effects of Bromide". United States.
@article{osti_895784,
title = {Oxygen Reduction Reaction on Pt(111): Effects of Bromide},
author = {Markovic, N M and Gasteiger, H A and Grgur, B N and Ross, Jr, P N},
abstractNote = {Using the rotating ring-disk technique (RRDE) the oxygenreduction reaction (orr) was studied on the Pt(111) surface in thepresence of Br- anions. We found that the orr at the Pt(111) Bradinterface is always accompanied quantitatively by H2O2 oxidation currentson the ring electrode, implying that in the presence of Br- anions theorr does not proceed entirely through the 4e- reduction pathway, as inthe Br--free solution. We propose that strongly adsorbed Br- cansimultaneously suppress both the adsorption of the O2 molecule and theformation of pairs of platinum sites needed for the breaking of the O-Obond. Besides elucidating the effects of Brad, these studies also shedsome light on the role of OHad on the kinetics of the orr on the Pt(111)surface in solution free of Br anions. We have developed a theoreticalmodel and from simulations of I-E curves we propose two modes of actionof the OHad state on the kinetics of the orr on the Pt(111) surface: (i)OHad can block the adsorption of O2 on active platinum sites, i.e. theycompete for the same sites, and (ii) OHad can alter the adsorption energyof intermediates which are formed during the orr on the bare Pt sitesadjacent to the OHad.},
doi = {},
url = {https://www.osti.gov/biblio/895784}, journal = {Journal of Electroanalytical Chemistry},
number = 1,
volume = 467,
place = {United States},
year = {1998},
month = {7}
}