Micron-Scale Diagnostics for Through-Plane Transport Phenomena in Porous Electrodes

2010 ◽  
Author(s):  
Katherine C. Hess ◽  
William K. Epting ◽  
Shawn Litster
Keyword(s):  
Hydrogen Oxidation ◽  
Polymer Electrolyte Membrane ◽  
Transport Phenomena ◽  
Reduction Reaction ◽  
Porous Electrodes ◽  
New Method ◽  
Hydrogen Oxidation Reaction ◽  
Electrolyte Membrane ◽  
Microstructured Electrode ◽  
Accuracy And Repeatability

This paper presents the development of a new method for characterizing the electrochemistry and transport phenomena in the porous electrodes of polymer electrolyte membrane fuel cells (PEMFCs). The new method uses a unique microstructured electrode scaffold (MES) that provide an architecture for obtaining measurements at discrete points through the thickness of an electrode. This paper reports on the design, fabrication and initial testing of an MES for measuring ionic potential across the thickness of a PEMFC’s cathode. The new fuel cell hardware and reference electrodes (REs), which gather electrolyte potential measurements through the thickness of the electrode via the MES, have been tested for accuracy and repeatability. The use of hydrogen oxidation reaction (HOR) REs versus oxygen reduction reaction (ORR) REs is analyzed and discussed. Polarization data was also gathered and the REs are used to separate the half-cell potentials. Finally, the preliminary fabrication of an MES and a micro-structural analysis are discussed.

scholarly journals Electrochemical Analysis for Demonstrating CO Tolerance of Catalysts in Polymer Electrolyte Membrane Fuel Cells

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1425 ◽  
Author(s):  
Min ◽  
Jeffery ◽  
Kim ◽  
Jung
Keyword(s):  
Fuel Cells ◽  
Polymer Electrolyte ◽  
Hydrogen Oxidation ◽  
Polymer Electrolyte Membrane ◽  
Co Adsorption ◽  
Electrochemical Analysis ◽  
Hydrogen Oxidation Reaction ◽  
Test Protocol ◽  
Electrolyte Membrane ◽  
Co Tolerance

Since trace amounts of CO in H2 gas produced by steam reforming of methane causes severe poisoning of Pt-based catalysts in polymer electrolyte membrane fuel cells (PEMFCs), research has been mainly devoted to exploring CO-tolerant catalysts. To test the electrochemical property of CO-tolerant catalysts, chronoamperometry is widely used under a CO/H2 mixture gas atmosphere as an essential method. However, in most cases of catalysts with high CO tolerance, the conventional chronoamperometry has difficulty in showing the apparent performance difference. In this study, we propose a facile and precise test protocol to evaluate the CO tolerance via a combination of short-term chronoamperometry and a hydrogen oxidation reaction (HOR) test. The degree of CO poisoning is systematically controlled by changing the CO adsorption time. The HOR polarization curve is then measured and compared with that measured without CO adsorption. When the electrochemical properties of PtRu alloy catalysts with different atomic ratios of Pt to Ru are investigated, contrary to conventional chronoamperometry, these catalysts exhibit significant differences in their CO tolerance at certain CO adsorption times. The present work will facilitate the development of catalysts with extremely high CO tolerance and provide insights into the improvement of electrochemical methods.

scholarly journals Development of Porous Pt Electrocatalysts for Oxygen Reduction and Evolution Reactions

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2398
Author(s):  
Marika Muto ◽  
Mayumi Nagayama ◽  
Kazunari Sasaki ◽  
Akari Hayashi
Keyword(s):  
Oxygen Reduction ◽  
Current Density ◽  
Polymer Electrolyte Membrane ◽  
Porous Metal ◽  
Pem Fuel Cells ◽  
Reduction Reaction ◽  
Electrolyte Membrane ◽  
Catalyst Layers ◽  
Pt Electrocatalysts ◽  
Pt Black

Porous Pt electrocatalysts have been developed as an example of carbon-free porous metal catalysts in anticipation of polymer electrolyte membrane (PEM) fuel cells and PEM water electrolyzers through the assembly of the metal precursor and surfactant. In this study, porous Pt was structurally evaluated and found to have a porous structure composed of connected Pt particles. The resulting specific electrochemical surface area (ECSA) of porous Pt was 12.4 m2 g−1, which was higher than that of commercially available Pt black. Accordingly, porous Pt showed higher oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity than Pt black. When the activity was compared to that of a common carbon-supported electrocatalyst, Pt/ketjen black (KB), porous Pt showed a comparable ORR current density (2.5 mA cm−2 at 0.9 V for Pt/KB and 2.1 mA cm−2 at 0.9 V for porous Pt), and OER current density (6.8 mA cm−2 at 1.8 V for Pt/KB and 7.0 mA cm−1 at 1.8 V), even though the ECSA of porous Pt was only one-sixth that of Pt/KB. Moreover, it exhibited a higher durability against 1.8 V. In addition, when catalyst layers were spray-printed on the Nafion® membrane, porous Pt displayed more uniform layers in comparison to Pt black, showing an advantage in its usage as a thin layer.

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