Kinetics of Oxide Formation and Reduction at Pt Catalyst in Polymer Electrolyte Fuel Cells

Suzuki, Tomomichi; Morimoto, Yu

doi:10.5796/electrochemistry.84.511

Cited by 7 publications

(6 citation statements)

References 24 publications

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“…Under the same initial oxide coverage, the reduction of surface oxides was observed to be more difficult when aged at lower potentials for longer durations compared to a higher potential for shorter durations. 11 In addition to surface oxidation, the impact of ionomer adsorption to the long term loss under potentiostatic conditions was recently revealed by Casalegno 41 and Kirsch. 42 In the present work, the transient ORR performance loss of Pt/C cathode catalyst was studied specifically at 0.8 V under MEA conditions due to its significance in meeting the future efficiency targets.…”

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confidence: 97%

“…7,8 For the same reason, the lifetime of the Pt catalyst is another important factor to be addressed, if not even more critical to ensure long term steady performance of PEMFCs. [9][10][11][12][13][14][15][16][17][18][19][20] Considering the foreseeable collaborative relation between PEMFCs and Li-ion batteries in automotive applications, in which batteries provide power and fuel cells provide drive range, PEMFCs will be expected to operate at conditions as efficient as possible. [21][22][23][24] Because the theoretical efficiency of PEMFCs is linearly dependent on their operating voltage, it would be beneficial if PEMFCs could operate at higher cathode potentials.…”

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confidence: 99%

“…Built upon these fundamental studies, recent efforts have became more application driven and the focus shifted from polycrystalline Pt to carbon supported platinum nanoparticle (Pt/C) cathode catalyst under membrane electrode assembly (MEA) conditions. These include, but are not limited to, the works of O'Grady, 37 Fenton, 38 Fuller, 39 Zhang, 28 Subramanian, 19 Jorné, 40 Suzuki, 11 and Casalegno. 41 The situation becomes more complicated under MEA testing conditions, as O'Grady showed surface oxide formation being enhanced by in situ generated water from the cathode half reaction.…”

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confidence: 99%

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Transient Loss and Recovery of Platinum Fuel Cell Cathode Catalyst at High Voltage Efficiency Regimes

Lin

Cheng

Liao

et al. 2021

J. Electrochem. Soc.

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The performance of oxygen reduction reaction (ORR) catalysts, typically evaluated by potential scanning techniques, fails to capture the significant activity decay occurring at longer time scales. To meet the 65% peak energy efficiency target, the continuous decay of Pt/C ORR catalyst, commonly referred to as “transient performance loss”, is studied at 0.8 V by chronoamperometry under membrane electrode assembly (MEA) testing conditions. Based on the results from the time-resolved cyclic voltammetry (CV), surface oxidation was identified as the primary cause of the transient loss. The reduction of surface oxide was observed to occur at 0.6 V, and the recovery of cathode performance can hence be achieved at equal or lower potentials. In addition, the effects of operating temperature and cathode humidity were also studied. The coverage of Pt surface oxides and the extent of the transient loss were both significantly reduced as temperature decreased. However, the benefit of a lower operating temperature came at the cost of slower recovery kinetics. In terms of the impact of humidity, the presence of liquid water was identified as the critical factor leading to a much more severe performance loss over time.

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Transient Loss and Recovery of Platinum Fuel Cell Cathode Catalyst at High Voltage Efficiency Regimes

Lin

Cheng

Liao

et al. 2021

J. Electrochem. Soc.

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“…17 According to Fick's law, the current density is a function of oxygen concentration gradience and transport resistance, which is highly dependent on the electrode structure. 22,36,37 In principle, the total oxygen transport (R total ) can be determined by measuring using a limiting current method shown in below,…”

Section: Resultsmentioning

confidence: 99%

Improve the Activity and Stability of PtCo/C Catalyst by Ionic Liquid in Proton Exchange Membrane Fuel Cell

Huang¹,

Lin²,

Zhou³

et al. 2022

J. Electrochem. Soc.

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Ionic liquid ([MTBD][C4F9SO3]) has been explored as a surface modification of PtCo/C catalyst to improve its performance and durability in a membrane electrode assembly (MEA). Compared to the pristine catalyst, the incorporation of ionic liquid (IL) increases the oxygen reduction reaction (ORR) activity of PtCo/C and reduces the gas and proton diffusion resistance of the cathode catalyst layer, resulting in considerably improved MEA performance. More importantly, IL largely slows the ORR activity decay. The PtCo/C-IL outperformed PtCo/C throughout the 30,000 potential cycles test, which is consistent with higher active surface area retention and less Co dissolution of PtCo/C-IL. This work suggests that IL modification can serve as a complementary approach to the development of novel electrocatalysts and electrode structures.

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“…Moreover, most of the applied studies using an operational fuel cell only qualitatively discuss the effect of platinum oxidation on the overall performance. [5,10,24,45] For a better understanding of this effect and in order to compare with fundamental studies, a quantitative investigation of the direct influence of PtO on the PEM fuel cell performance is needed. Recently, Bernhard et al [46] addressed this issue and published a quantitative study of the voltage loss in PEM fuel cells due to platinum oxidation.…”

Section: Introductionmentioning

confidence: 99%

The influence of platinum surface oxidation on the performance of a polymer electrolyte membrane fuel cell—probing changes of catalytically active surface sites on a polycrystalline platinum electrode for the oxygen reduction reaction

Eckl

Mattausch

Jung

et al. 2021

Electrochemical Science Adv

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To obtain fundamental insights into the performance of polymer electrolyte membrane (PEM) fuel cells, we perform a parallel investigation of the influence of platinum surface oxide (PtO) formation on the electrocatalytic activity toward the oxygen reduction reaction (ORR) for a polycrystalline platinum electrode in comparison with a commercial PEM fuel cell. PtO is formed by holding both systems at a constant potential for a given period of time. Conditioning potentials between 0.5 and 1.0 V versus SHE and conditioning times from 5 s up to 10 h are explored, respectively. We find that the voltage difference of the ORR between the oxidized and oxide‐free states depends on both the conditioning potential as well as the conditioning time at a given potential and furthermore increases with the applied target current. The change of the voltage loss over time, the so‐called voltage loss rate α, shows a maximum at potentials between 0.85 and 0.9 V and increases with increasing current density. We discuss various hypotheses to explain these findings obtained by linear voltammetry, Tafel slope analysis, Auger electron spectroscopy, and atomic force microscopy experiments. Finally, we conclude that the voltage loss rate is influenced by changes in the relative electrocatalytic activity of different crystal facets for the ORR as the oxide coverage varies.

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Kinetics of Oxide Formation and Reduction at Pt Catalyst in Polymer Electrolyte Fuel Cells

Cited by 7 publications

References 24 publications

Transient Loss and Recovery of Platinum Fuel Cell Cathode Catalyst at High Voltage Efficiency Regimes

Transient Loss and Recovery of Platinum Fuel Cell Cathode Catalyst at High Voltage Efficiency Regimes

Improve the Activity and Stability of PtCo/C Catalyst by Ionic Liquid in Proton Exchange Membrane Fuel Cell

The influence of platinum surface oxidation on the performance of a polymer electrolyte membrane fuel cell—probing changes of catalytically active surface sites on a polycrystalline platinum electrode for the oxygen reduction reaction

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