In situ voltammetric characterization of PEM fuel cell catalyst layers

Heikki Kumpulainen, Terttu Peltonen, Ulla Koponen, Mikael Bergelin, Matti Valkiainen, Mikael Wasberg

Research output: Book/ReportReportProfessional

Abstract

In our work we have studied in-house made MEA:s (geometric area 5 cm2) based on commercial (E-TEK, Inc.) carbon supported Pt and Pt/Ru catalysts. A Nafion 115 membrane was coated with ink containing Pt/C catalyst and Nafion solution and dried layers were sintered by hot pressing. After post-processing the membranes were installed in a single cell test fixture. In addition, the ink used for coating was characterized in thin film form in sulphuric acid electrolyte and the results were compared to the fuel cell data. Current-voltage characteristics were measured after a running-in period of about 16 hours. After cooling the test fixture down to room temperature the cyclic voltammograms were taken in situ by using a two-electrode potentiostatic measurement circuit. The electrode under study is purged by an inert gas (N2) while the other electrode is purged by hydrogen gas so as to form a reversible hydrogen electrode. In this manner the surface processes taking place on both the anode and cathode side of the MEA could be measured and evaluated. From the hydrogen desorption charge on Pt the available Pt surface area has been determined and the ratio between measured area and calculated total Pt area was in the range of 30%. The ratios between electrochemical surface areas on the anode and cathode side compare well with the corresponding ratios obtained from calculations of total added Pt surface area. The relation between the voltammetrically obtained surface areas and the polarization data (current-voltage curves) is discussed. An enlargement of the active surface area could be noted after potential scans into the Pt oxide formation region This indicates the presence of a deactivation process, probably due to adsorbed organic material removed oxidatively during the extended polarization. When MEAs based on Pt/Ru alloy catalysts were measured the hydrogen adsorption charge decreased as a result of the lower hydrogen adsorption capability of Ru. In the double layer region the formation of Ru-oxides was also well manifested.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages36
ISBN (Electronic)951-38-5888-X
ISBN (Print)951-38-5887-1
Publication statusPublished - 2002
MoE publication typeNot Eligible

Publication series

NameVTT Tiedotteita - Research Notes
PublisherVTT
No.2137
ISSN (Print)1235-0605
ISSN (Electronic)1455-0865

Fingerprint

Fuel cells
Hydrogen
Catalysts
Electrodes
Ink
Oxides
Anodes
Cathodes
Polarization
Membranes
Noble Gases
Adsorption
Hot pressing
Current voltage characteristics
Electrolytes
Desorption
Carbon
Gases
Cooling
Thin films

Keywords

  • fuel cells
  • PEMFC
  • catalysts
  • layers
  • membrane electrodes
  • characteristics
  • measurement
  • electric current
  • voltage
  • cyclic voltammetry

Cite this

Kumpulainen, H., Peltonen, T., Koponen, U., Bergelin, M., Valkiainen, M., & Wasberg, M. (2002). In situ voltammetric characterization of PEM fuel cell catalyst layers. Espoo: VTT Technical Research Centre of Finland. VTT Tiedotteita - Research Notes, No. 2137
Kumpulainen, Heikki ; Peltonen, Terttu ; Koponen, Ulla ; Bergelin, Mikael ; Valkiainen, Matti ; Wasberg, Mikael. / In situ voltammetric characterization of PEM fuel cell catalyst layers. Espoo : VTT Technical Research Centre of Finland, 2002. 36 p. (VTT Tiedotteita - Research Notes; No. 2137).
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Kumpulainen, H, Peltonen, T, Koponen, U, Bergelin, M, Valkiainen, M & Wasberg, M 2002, In situ voltammetric characterization of PEM fuel cell catalyst layers. VTT Tiedotteita - Research Notes, no. 2137, VTT Technical Research Centre of Finland, Espoo.

In situ voltammetric characterization of PEM fuel cell catalyst layers. / Kumpulainen, Heikki; Peltonen, Terttu; Koponen, Ulla; Bergelin, Mikael; Valkiainen, Matti; Wasberg, Mikael.

Espoo : VTT Technical Research Centre of Finland, 2002. 36 p. (VTT Tiedotteita - Research Notes; No. 2137).

Research output: Book/ReportReportProfessional

TY - BOOK

T1 - In situ voltammetric characterization of PEM fuel cell catalyst layers

AU - Kumpulainen, Heikki

AU - Peltonen, Terttu

AU - Koponen, Ulla

AU - Bergelin, Mikael

AU - Valkiainen, Matti

AU - Wasberg, Mikael

PY - 2002

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N2 - In our work we have studied in-house made MEA:s (geometric area 5 cm2) based on commercial (E-TEK, Inc.) carbon supported Pt and Pt/Ru catalysts. A Nafion 115 membrane was coated with ink containing Pt/C catalyst and Nafion solution and dried layers were sintered by hot pressing. After post-processing the membranes were installed in a single cell test fixture. In addition, the ink used for coating was characterized in thin film form in sulphuric acid electrolyte and the results were compared to the fuel cell data. Current-voltage characteristics were measured after a running-in period of about 16 hours. After cooling the test fixture down to room temperature the cyclic voltammograms were taken in situ by using a two-electrode potentiostatic measurement circuit. The electrode under study is purged by an inert gas (N2) while the other electrode is purged by hydrogen gas so as to form a reversible hydrogen electrode. In this manner the surface processes taking place on both the anode and cathode side of the MEA could be measured and evaluated. From the hydrogen desorption charge on Pt the available Pt surface area has been determined and the ratio between measured area and calculated total Pt area was in the range of 30%. The ratios between electrochemical surface areas on the anode and cathode side compare well with the corresponding ratios obtained from calculations of total added Pt surface area. The relation between the voltammetrically obtained surface areas and the polarization data (current-voltage curves) is discussed. An enlargement of the active surface area could be noted after potential scans into the Pt oxide formation region This indicates the presence of a deactivation process, probably due to adsorbed organic material removed oxidatively during the extended polarization. When MEAs based on Pt/Ru alloy catalysts were measured the hydrogen adsorption charge decreased as a result of the lower hydrogen adsorption capability of Ru. In the double layer region the formation of Ru-oxides was also well manifested.

AB - In our work we have studied in-house made MEA:s (geometric area 5 cm2) based on commercial (E-TEK, Inc.) carbon supported Pt and Pt/Ru catalysts. A Nafion 115 membrane was coated with ink containing Pt/C catalyst and Nafion solution and dried layers were sintered by hot pressing. After post-processing the membranes were installed in a single cell test fixture. In addition, the ink used for coating was characterized in thin film form in sulphuric acid electrolyte and the results were compared to the fuel cell data. Current-voltage characteristics were measured after a running-in period of about 16 hours. After cooling the test fixture down to room temperature the cyclic voltammograms were taken in situ by using a two-electrode potentiostatic measurement circuit. The electrode under study is purged by an inert gas (N2) while the other electrode is purged by hydrogen gas so as to form a reversible hydrogen electrode. In this manner the surface processes taking place on both the anode and cathode side of the MEA could be measured and evaluated. From the hydrogen desorption charge on Pt the available Pt surface area has been determined and the ratio between measured area and calculated total Pt area was in the range of 30%. The ratios between electrochemical surface areas on the anode and cathode side compare well with the corresponding ratios obtained from calculations of total added Pt surface area. The relation between the voltammetrically obtained surface areas and the polarization data (current-voltage curves) is discussed. An enlargement of the active surface area could be noted after potential scans into the Pt oxide formation region This indicates the presence of a deactivation process, probably due to adsorbed organic material removed oxidatively during the extended polarization. When MEAs based on Pt/Ru alloy catalysts were measured the hydrogen adsorption charge decreased as a result of the lower hydrogen adsorption capability of Ru. In the double layer region the formation of Ru-oxides was also well manifested.

KW - fuel cells

KW - PEMFC

KW - catalysts

KW - layers

KW - membrane electrodes

KW - characteristics

KW - measurement

KW - electric current

KW - voltage

KW - cyclic voltammetry

M3 - Report

SN - 951-38-5887-1

T3 - VTT Tiedotteita - Research Notes

BT - In situ voltammetric characterization of PEM fuel cell catalyst layers

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Kumpulainen H, Peltonen T, Koponen U, Bergelin M, Valkiainen M, Wasberg M. In situ voltammetric characterization of PEM fuel cell catalyst layers. Espoo: VTT Technical Research Centre of Finland, 2002. 36 p. (VTT Tiedotteita - Research Notes; No. 2137).