Modeling of single catalyst particle in cathode of PEM fuel cells

Yan, Qiangu; Wu, Junxiao

doi:10.1016/j.enconman.2008.01.021

Cited by 23 publications

(7 citation statements)

References 43 publications

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“…This suggests that the 4.9 nm Pt3Co particles on the carbon support would be ~2 times closer to each other (using the metric of geometric distance) than the 8.1 nm Pt3Co particles and ~4 times closer when compared to the 14.8 nm particles. Fewer particles in electrodes could result in fewer access points for ORR, and lower net oxygen concentration at the catalyst surface, resulting in lower performance with larger particles [39]. The effect of this catalyst particle spacing is expected to be greater on the performance in air than in oxygen, as seen in Figure 2.…”

Section: Resultsmentioning

confidence: 84%

Effect of Particle Size and Operating Conditions on Pt3Co PEMFC Cathode Catalyst Durability

et al. 2015

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Abstract:The initial performance and decay trends of polymer electrolyte membrane fuel cells (PEMFC) cathodes with Pt3Co catalysts of three mean particle sizes (4.9 nm, 8.1 nm, and 14.8 nm) with identical Pt loadings are compared. Even though the cathode based on 4.9 nm catalyst exhibited the highest initial electrochemical surface area (ECA) and mass activity, the cathode based on 8.1 nm catalyst showed better initial performance at high currents. Owing to the low mass activity of the large particles, the initial performance of the 14.8 nm Pt3Co-based electrode was the lowest. The performance decay rate of the electrodes with the smallest Pt3Co particle size was the highest and that of the largest Pt3Co particle size was lowest. Interestingly, with increasing number of decay cycles (0.6 to 1.0 V, 50 mV/s), the relative improvement in performance of the cathode based on 8.1 nm Pt3Co over the 4.9 nm Pt3Co increased, owing to better stability of the 8.1 nm catalyst. The electron OPEN ACCESSCatalysts 2015, 5 927 microprobe analysis (EMPA) of the decayed membrane-electrode assembly (MEA) showed that the amount of Co in the membrane was lower for the larger particles, and the platinum loss into the membrane also decreased with increasing particle size. This suggests that the higher initial performance at high currents with 8.1 nm Pt3Co could be due to lower contamination of the ionomer in the electrode. Furthermore, lower loss of Co from the catalyst with increased particle size could be one of the factors contributing to the stability of ECA and mass activity of electrodes with larger cathode catalyst particles. To delineate the impact of particle size and alloy effects, these results are compared with prior work from our research group on size effects of pure platinum catalysts. The impact of PEMFC operating conditions, including upper potential, relative humidity, and temperature on the alloy catalyst decay trends, along with the EMPA analysis of the decayed MEAs, are reported.

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Section: Resultsmentioning

confidence: 84%

Effect of Particle Size and Operating Conditions on Pt3Co PEMFC Cathode Catalyst Durability

et al. 2015

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“…Indeed, by introducing a way to modulate the current transfer density, it allows for better prediction [1]. Various models can be found in the literature [161][162][163].…”

Section: Transport Modelsmentioning

confidence: 99%

Performance and degradation of Proton Exchange Membrane Fuel Cells: State of the art in modeling from atomistic to system scale

Jahnke

Futter

Latz

et al. 2016

Journal of Power Sources

207

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Proton Exchange Membrane Fuel Cells (PEMFC) are energy efficient and environmentally friendly alternatives to conventional energy conversion systems in many yet emerging applications. In order to enable prediction of their performance and durability, it is crucial to gain a deeper understanding of the relevant operation phenomena, e.g., electrochemistry, transport phenomena, thermodynamics as well as the mechanisms leading to the degradation of cell components. Achieving the goal of providing predictive tools to model PEMFC performance, durability and degradation is a challenging task requiring the development of detailed and realistic models reaching from the atomic/molecular scale over the meso scale of structures and materials up to components, stack and system level. In addition an appropriate way of coupling the different scales is required. This review provides a comprehensive overview of the state of the art in modeling of PEMFC, covering all relevant scales from atomistic up to system level as well as the coupling between these scales. Furthermore, it focuses on the modeling of PEMFC degradation mechanisms and on the coupling between performance and degradation models.

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“…/ . In another study, the effective thermal conductivity was, in a similar way based on the pore-level dimensionless temperature distribution, evaluated by the one-equation average model describing the conduction heat transfer in the porous media [25]: (5) where T 1 and T 2 are the temperatures at the top and bottom walls, respectively, l is the length. The obtained effective conductivity is presented as a function of the solid and fl uid conductivities, and this value was compared with the extreme ones from parallel and serial structures at the same porosity.…”

Section: Effective Thermal Conductivity and Modelsmentioning

confidence: 99%

“…Various heat transfer processes appearing in heterogeneously distributed pores and solid matrices are strongly coupled with catalytic reactions and charge (proton/ions and electrons) transfer, e.g. in proton exchange membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs) [4][5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of models of the effective thermal conductivity of porous materials relevant to fuel cell electrodes

Sundén¹,

Yuan²

2013

Int. J. CMEM

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Small scale solid particles with fl uid-fi lled pores are applied in various porous structures in energy systems, such as fuel cells, for the objectives to enhance the catalytic reaction activities and improve the fuel utilization effi ciency or/and reduce the pollutants. In addition to the catalytic reactions, heat transfer processes in fuel cell porous electrodes are strongly affected by the small scale and complex porous structures. In this paper, the thermal energy equation commonly used for continuum models at porous-averaging level is highlighted, with the purpose to provide a general overview of the validity and limiting conditions for its application. Models for effective thermal conductivity are reviewed and discussed. It is found that both the rarefaction and tortuosity effects on reduction of effective thermal conductivity may be signifi cant, and these should be evaluated based on detailed information of operating parameters, pore size distributions and topologic structures. Comments and suggestions are presented for the better understanding and implementation of the continuum heat transfer models for fuel cell electrodes.

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Modeling of single catalyst particle in cathode of PEM fuel cells

Cited by 23 publications

References 43 publications

Effect of Particle Size and Operating Conditions on Pt3Co PEMFC Cathode Catalyst Durability

Effect of Particle Size and Operating Conditions on Pt3Co PEMFC Cathode Catalyst Durability

Performance and degradation of Proton Exchange Membrane Fuel Cells: State of the art in modeling from atomistic to system scale

Evaluation of models of the effective thermal conductivity of porous materials relevant to fuel cell electrodes

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