Gas transport inside and outside carbon supports of catalyst layers for PEM fuel cells

Iden, Hiroshi; Mashio, Tetsuya; Ohma, Atsushi

doi:10.1016/j.jelechem.2013.09.011

Cited by 38 publications

(38 citation statements)

References 21 publications

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“…Toyota, General Motors, and Nissan have suggested that the gas‐transport resistance obtained from this technique can include resistance in the ionomer surrounding the electrocatalyst . Furthermore, because the cathode platinum loading is 0.1 mg Pt cm −2 in this study, the resistance in the ionomer might be preferentially evaluated .…”

Section: Resultsmentioning

confidence: 99%

Analysis of the Microstructure Formation Process and Its Influence on the Performance of Polymer Electrolyte Fuel‐Cell Catalyst Layers

et al. 2015

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To understand the formation process of the microstructure of the catalyst layer of a polymer electrolyte fuel cell (PEFC), we tried to observe the “real” structure of the catalyst ink by cryogenic scanning electron microscopy (cryo‐SEM). Catalyst inks with different water/alcohol compositions were successfully visualized, and they correlated well with the particle‐size distribution obtained by laser diffraction of the ink and the structures of the catalyst layers obtained by typical SEM. On the basis of other electrochemical characterization results, including current–voltage performance, oxygen reduction reaction kinetics, and mass‐transport properties, the microstructures of the catalyst inks and the catalyst layers were proposed. The proposed microstructures can explain the relationship between the catalyst materials and the performance of the cathode catalyst layer of the membrane electrode assembly through its formation and apparent properties. It was also found that the microstructure of the catalyst ink plays an important role in performance.

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Section: Resultsmentioning

confidence: 99%

Analysis of the Microstructure Formation Process and Its Influence on the Performance of Polymer Electrolyte Fuel‐Cell Catalyst Layers

et al. 2015

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“…The internal particles have been shown to be mostly electrochemically active and are believed to have access to proton and O 2 through small openings (1-5 nm) in the carbon micropores [40,41]. But it is believed that the pores are too small for ionomer to intrude and form a direct proton conduction path to the Pt surface [39,[42][43][44][45]. Although it is hypothesized that condensed water can conduct protons in these pores, much remains unclear on the exact mechanism and the magnitude of the proton conductivity [46][47][48].…”

Section: Pem Fuel Cell Electrodesmentioning

confidence: 99%

Proton-Exchange Membrane Fuel Cells with Low-Pt Content

Kongkanand¹,

Gu²,

Mathias

2017

Encyclopedia of Sustainability Science and Technology

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Widespread commercialization of fuel cell electric vehicles (FCEV) relies on further reduction of PGM (platinum group metals) usage. Although enhancements in the activity and stability of the catalyst are necessary, those alone are insufficient. In a fuel cell with low PGM content, transport of reactants (oxygen and protons) to a small area of catalyst can cause large performance loss at high power. Because it is this high-power point that determines the required fuel cell area, these losses drive up the size, and thus the cost, of the fuel cell stack. This entry discusses fuel cell cost reduction with special focus on the challenges and opportunity associated with Pt reduction. Proton-Exchange Membrane Fuel Cells with Low-Pt Content, Fig. 1 Impact of fuel cell vehicles on Pt consumption (Reprinted with permission from Ref. [7].

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“…Previous works showed that a higher gas transport resistance was observed inside of pores than outside of pores for Pt catalysts with porous carbon supports, especially at high relative humidity. 30 Moreover, a much higher local oxygen transport resistance of Pt/HSC (high surface area) is measured than that of Pt/Vu (medium surface area) due its unsuitable pore structure. 62,63 The depth and shape of the pore will directly affect the O 2 transport.…”

Section: Resultsmentioning

confidence: 99%

“…However, it is well known that ionomers are blocked outside the pores and lead to higher transport resistance and lower performance. [28][29][30] Therefore, the contradiction is that the Pt particles deposited inside the pores alleviate the ORR kinetic loss but at the expense of increased proton conduct ohmic resistance and oxygen transport resistance, while Pt particles on the surface of carbon suffer from severe activity loss. 8 This reflects that the design of the catalyst structure is quite significant for performance improvement.…”

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confidence: 99%

Solving Nafion poisoning of ORR catalysts with an accessible layer: designing a nanostructured core‐shell Pt/C catalyst via a one‐step self‐assembly for PEMFC

et al. 2020

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A core-shell Pt/C@NCL300 catalyst with an accessible layer was designed to recover lost ORR activity and was constructed via a one-step self-assembly process in this paper. A thin porous layer derived from Nafion was first formed on the surface of Pt/C catalyst to create a shell. This first coating successfully separated the Nafion and Pt particles in the catalysts and reducing the negative impact of Nafion on ORR activity and enhancing the fuel cell performance. The newly fabricated Pt/C@NCL300 catalyst exhibited much higher specific activity than the original Pt/C catalyst in RDE tests under the same conditions and were comparable to the activity of Pt/C electrode without Nafion poisoning. Moreover, the fuel cell with Pt/C@NCL300 catalyst exhibited a higher power density without an obvious increase in proton transport and O 2 transport resistance compared to that of a Pt/C fuel cell with a low Pt loading. This result indicates that coating the Pt/C catalyst with a layer accessible for oxygen and protons is a promising way to effectively promote Pt-based catalysts that work under normal operating conditions.

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Gas transport inside and outside carbon supports of catalyst layers for PEM fuel cells

Cited by 38 publications

References 21 publications

Analysis of the Microstructure Formation Process and Its Influence on the Performance of Polymer Electrolyte Fuel‐Cell Catalyst Layers

Analysis of the Microstructure Formation Process and Its Influence on the Performance of Polymer Electrolyte Fuel‐Cell Catalyst Layers

Proton-Exchange Membrane Fuel Cells with Low-Pt Content

Solving Nafion poisoning of ORR catalysts with an accessible layer: designing a nanostructured core‐shell Pt/C catalyst via a one‐step self‐assembly for PEMFC

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