Using corrosion-like processes to remove poisons from electrocatalysts: a viable strategy to chemically regenerate irreversibly poisoned polymer electrolyte fuel cells

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Title: Using corrosion-like processes to remove poisons from electrocatalysts: a viable strategy to chemically regenerate irreversibly poisoned polymer electrolyte fuel cells
Authors: Kucernak, ARJ
Kakati
Fahy, KF
Item Type: Journal Article
Abstract: Poisoning of Pt/C catalysts due to SO2 on a rotating disk electrode (RDE), and as part of the cathode layer in a single cell fuel cell and fuel cell stack are studied in terms of the system performance, and the effect of electrochemical and chemical post treatment to remove the adsorbed sulphur containing species. It is found that external polarisation can only recover the ORR performance of catalyst on an RDE after SO2 poisoning when an applied potential of 1.6 V(RHE) is used for 1 ks. An alternative approach is to use ozone, as in the presence of this species, the electrode potential is raised to ~1.6V(RHE) due to the high potential of the ozone reduction reaction. The high open circuit potential leads to a mixed potential and was found also to be highly efficient at removing the poison via coupled ozone reduction and poison oxidation. The ozone process is found to work efficiently at the catalyst level as shown through rotating disk electrode studies and also in single cell fuel cells. Furthermore we demonstrate for the first time the recovery of a SO2 poisoned fuel cell stack using the mixed-potential approach and ozone as a reactant. The cleaning process is fast (~10 minutes), occurs at room temperature, and does not require any special modification to the fuel cell. The process may be applicable to a wide range of poisons which can be oxidatively removed from platinum at high potentials.
Issue Date: 15-Nov-2016
Date of Acceptance: 9-Nov-2016
URI: http://hdl.handle.net/10044/1/42505
DOI: https://dx.doi.org/10.1016/j.electacta.2016.11.054
ISSN: 1873-3859
Publisher: Elsevier
Start Page: 888
End Page: 897
Journal / Book Title: Electrochimica Acta
Volume: 222
Copyright Statement: © 2016 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Technology Strategy Board
Funder's Grant Number: EP/I037024/1
CHIS_P55265
Keywords: Energy
03 Chemical Sciences
09 Engineering
02 Physical Sciences
Publication Status: Published
Appears in Collections:Chemistry
Faculty of Natural Sciences



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