Low Pt loading high performance cathodes for PEM fuel cells

Qi, Zhigang; Kaufman, Arthur

doi:10.1016/s0378-7753(02)00477-9

Cited by 262 publications

(142 citation statements)

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“…on the electrochemical performance of the cathodes in a bacteria-free electrochemical cell using chronopotentiometry. Unlike what can be expected from conventional FCs where the performance is greatly affected by Pt loading, 69 they found that lowering the Pt loading by a factor of 5 caused only a small reduction in the overall MFC performance, which may be acceptable considering the cost of the catalyst and the large surface areas needed for MFC operation. Of course, this result should be assessed in light of the substantial differences between FCs and MFCs, since ambient temperature, ionic strength, and mostly neutral pH may pose major thermodynamic and kinetic constraints on MFCs cathode performance.…”

Section: Cathodementioning

confidence: 78%

Engineering materials and biology to boost performance of microbial fuel cells: a critical review

Rinaldi

Mecheri

Garavaglia³

et al. 2008

Energy Environ. Sci.

335

233

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In less than a decade the levels of performance of microbial fuel cells (MFCs) in terms of current output, voltage, and power density have grown tremendously according to steady exponential trends. Achievements occurred over the past 2-3 years have been particularly impressive. This is due partly to a better understanding of the biological aspects of this multidisciplinary technology, but also to systematic work undertaken by several research groups worldwide aimed at improving and optimizing aspects related to materials and system configuration. Aim of this review is to outline the current perspective about MFCs by focusing on the recent major advances in the areas of materials and engineering. MFCs are promising devices to address sustainability concerns both in terrestrial and space applications.

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Section: Cathodementioning

confidence: 78%

Engineering materials and biology to boost performance of microbial fuel cells: a critical review

Rinaldi

Mecheri

Garavaglia³

et al. 2008

Energy Environ. Sci.

335

233

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“…Figures 10b and 10c match qualitatively the trends seen in experiments. [29][30][31] The drop in performance for Pt loading >0.35 mg/cm 2 in Figs. 10b and 10c can be attributed to decreased porosity at higher Pt loadings which reduces the effective surface area.…”

Section: Resultsmentioning

confidence: 99%

An Improved Agglomerate Model for the PEM Catalyst Layer with Accurate Effective Surface Area Calculation Based on the Sphere-Packing Approach

Cetinbas

Advani

Prasad

2014

J. Electrochem. Soc.

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The complex porous structure of the PEM fuel cell catalyst layer (CL) necessitates the use of multiscale modeling strategies such as the agglomerate approach. In this study a 2D steady-state model for the cathode CL is developed using the spherical agglomerate approach. A new, more accurate, method is introduced to determine the effective agglomerate surface area, which plays a key role in estimating diffusion losses in the CL. Specifically, the reduction in the effective surface area due to overlapping particles is modeled geometrically based on a sphere-packing approach. In addition, the equations for the agglomerate model are reformulated to correctly account for the agglomerate surface area reduction due to overlapping particles. The importance of an accurate geometric model for the effective surface area is demonstrated by investigating the effect of CL composition on performance, and the results show that the new method provides more realistic predictions than the existing approach. Results from the new approach for optimal Pt loading, ionomer loading, and Pt|C ratio show good agreement with experimental results. Great strides have been made in proton exchange membrane (PEM) fuel cell research since the introduction of the technology in the early 1960s. Computational models represent a major tool for the design and development of PEM fuel cells because they decrease the dependence on expensive and time-consuming experimental procedures. Accurate computational models can also provide key insights into the fundamental processes that govern fuel cell performance. The overall accuracy of computational models depends strongly on the description of the catalyst layer (CL) as all the critical electrochemical reactions, and heat and mass transport processes occur within the CL. Therefore, developing better modeling strategies for the CL has been an important research objective to obtain a realistic representation of PEM fuel cell behavior.Catalyst layer modeling approaches, which have grown in complexity in the past decades, were described in detail in. 1 Here, we present only a brief review. Among the models reported, the interface model 2-4 is the simplest approach as it represents all of the CL activity as boundary conditions applied at the interface between the membrane and the gas diffusion layer (GDL). The macro-homogenous model [4][5][6][7] is a more advanced approach that utilizes the effective medium theory and approximates the CL as a porous matrix of gas pores, platinum, carbon, and electrolyte. The most comprehensive device-level model to date is the agglomerate approach [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] as it represents CL activity as a multiscale problem. Overall, the CL is assumed to consist of gas pores and aggregates of C|Pt particles that are covered by an electrolyte film. The agglomerate approach attempts to model the C|Pt aggregates (shown schematically in Fig. 1a) that are typically seen in microscopic images of the CL. For simplicity, the aggregate microstructure, de...

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“…the dry weight of Nafion ionomer divided by the geometric area of the electrode or as wt% of Nafion (dry weight of Nafion ionomer divided by the total weight of Pt + C and Nafion ionomer, multiplied by 100 [13]). The optimum Nafion content reported in the literature is generally in the range of 30-36 wt% irrespective of the Pt loading on Vulcan XC-72 for PEMFCs [11,[16][17][18], while the optimal Nafion content seems to be ca. 22 wt% for DMFCs [19] Although many studies have reported the effect of the Nafion content, somewhat different optimum Nafion contents are reported by different researchers.…”

mentioning

confidence: 93%

The Influence of Pt Loading, Support and Nafion Content on the Performance of Direct Methanol Fuel Cells: Examined on the Example of the Cathode

et al. 2011

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Nano‐sized Pt colloids were prepared using the polyol method and supported on Ketjen black EC 600J (KB), Vulcan XC‐72 (VC) and high surface area graphite 300 (HG). The effects of the Nafion ionomer content, and the Pt loading of the cathode catalyst layer as well as the Pt loading on the support on the performance of direct methanol fuel cells (DMFCs), were studied. The membrane electrode assemblies (MEAs) were analysed using current–voltage curves, cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and adsorbed CO stripping voltammetry. Optimum Nafion to carbon (N/C) ratios (N/C being defined as the weight ratio of the Nafion ionomer to the carbon) were determined. The optimum N/C ratios were found to depend on the support as follows, 1.4, 0.7 and 0.5 for Pt/KB, Pt/VC and Pt/HG, respectively and to be independent of the Pt/C loading range of 20–80 wt% tested in this work. The highest DMFC performances, as well as the highest electrochemical active surface areas, and improved gas diffusivities, were achieved using these ratios. For the catalysts prepared in this work, the average Pt crystallite size was found to decrease with increasing surface area of the support for a particular Pt loading. MEAs made using KB as support and the optimal N/C ratio of 1.4 showed the best performances, i.e. higher than the VC and HG supports for any N/C ratio. The highest DMFC performance was observed using 60 wt% Pt on KB cathode electrodes of 1 mg Pt cm–2 loading and an N/C value of 1.4. For all three supports studied, the 60 wt% Pt on carbon loading resulted in the best DMFC performance. This may be linked to the Pt particle size and catalyst preparation method used in this work. In comparison to literature results, high DMFC performances were achieved using relatively ‘low' Pt and Ru loadings. For example, a maximum power density of >100 mW cm–2 at 60 °C was observed using a 1 mg Pt cm–2 cathode loading and a 2 mg PtRu cm–2 anode loading.

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Low Pt loading high performance cathodes for PEM fuel cells

Cited by 262 publications

References 13 publications

Engineering materials and biology to boost performance of microbial fuel cells: a critical review

Engineering materials and biology to boost performance of microbial fuel cells: a critical review

An Improved Agglomerate Model for the PEM Catalyst Layer with Accurate Effective Surface Area Calculation Based on the Sphere-Packing Approach

The Influence of Pt Loading, Support and Nafion Content on the Performance of Direct Methanol Fuel Cells: Examined on the Example of the Cathode

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