2. Phosphoric acid fuel cells (PAFCs)

doi:10.1016/0360-5442(86)90097-6

Cited by 44 publications

(3 citation statements)

References 42 publications

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“…Among them Jalan and Taylor have extensively studied the ORR on carbon black-supported Pt alloys and claimed that shortening of Pt−Pt interatomic distances by alloying plays a major role in activity enhancement. Appleby claimed that the lattice contractions due to alloying results in a more favorable Pt−Pt distance for the dissociative adsorption of O 2 , while maintaining the favorable Pt electronic property. Mukerjee and Srinivasan 29 supported the view of favorable Pt−Pt distances in supported Pt binary alloys in PEFCs.…”

Section: Resultsmentioning

confidence: 99%

An Investigation of Structure−Catalytic Activity Relationship for Pt−Co/C Bimetallic Nanoparticles toward the Oxygen Reduction Reaction

et al. 2007

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Carbon-supported Pt−Co alloy nanoparticle catalysts of nominal atomic composition but with different alloying extents were prepared via a modified Watanabe process by employing microwave heating. Their structure was studied by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) techniques. Transmission electron microscopy (TEM) images indicated that the in-house-prepared Pt−Co alloy nanoparticles (sample-1 and sample-2) were well dispersed on the surface of the carbon support with narrow particle size distribution which is consistent with XRD grain size values. The catalyst composition obtained from XAS was nearly the same as that of the nominal value (1:1). The alloying extent values of Pt calculated from XAS measurements for sample-2 is similar to that of the commercial E-tek Pt−Co/C. This observation demonstrates the practical viability of our preparation protocol for Pt−Co/C catalysts. A comparative study was made for the oxygen reduction reaction (ORR) using a thin-film rotating disk electrode method to evaluate the catalytic behavior of Pt−Co/C and Pt/C catalyst with similar metal loadings and particle sizes. As compared to the Pt/C catalyst, the bimetallic Pt−Co/C of sample-2 exhibited an enhancement factor of 3 in mass activity at 0.95 V toward ORR. The enhancement in activity of sample-2 is similar in magnitude to that of the commercial E-tek Pt−Co/C catalyst. It is found that that the samples possessing a high alloying extent of Pt in the cluster enhances the activity of the bimetallic Pt−Co/C toward ORR. This observation confirms that the alloying extent of Pt is an important parameter by which one can have control over the fine-tuning of the catalytic activities of bimetallic nanoclusters. This activity enhancement may originate from the favorable electronic effects of a well mixed alloy underneath a thin “Pt-rich skin” structure of the Pt−Co bimetallic nanoparticles. This kind of thin “Pt-rich skin” is created by the dissolution of Co oxide on Pt−Co bimetallic nanoparticles while washing in acidic electrolyte before being subjected to ORR.

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Section: Resultsmentioning

confidence: 99%

An Investigation of Structure−Catalytic Activity Relationship for Pt−Co/C Bimetallic Nanoparticles toward the Oxygen Reduction Reaction

et al. 2007

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“…Conflicting results on electrocatalytic activity , and dissolution of non-noble metal components in the PAFC environment , suggested the possibility of differences in the electrochemical properties of bulk versus supported alloy electrocatalysts . Thus, the improvement for the ORR activity observed in gas diffusion electrodes for several Pt-alloy electrocatalysts could be attributed to factors specific of small particle size catalysts or related to the structural factors of the cell geometry.…”

Section: Introductionmentioning

confidence: 99%

Structure and Activity of Carbon-Supported Pt−Co Electrocatalysts for Oxygen Reduction

2004

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Carbon-supported Pt-Co electrocatalysts in the Pt:Co atomic ratio 85:15, mainly for application in polymer electrolyte fuel cells, have been prepared by different methods. The materials were tested in single cells with respect to the oxygen reduction reaction and their performances were compared. Of the several methods considered, the preparation of the electrocatalyst via the deposition and reduction of a Co precursor on previously formed carbon-supported platinum gave the best results. By increasing the Co content, a decrease of metal particle size and an improvement in the activity for the ORR of these catalysts was observed. For the electrocatalysts with a Pt:Co atomic ratio of 75:25, a good stability upon cycling was also found.

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“…Therefore, great efforts have been made to identify and develop superior Pt catalysts for oxygen reduction. Many studies have reported that platinum alloy catalysts have been found to display increased catalytic activity for oxygen reduction. − These nanodispersed particles of Pt alloys were found to show improved intrinsic activity and stability over pure Pt. ,− The Pt alloy is formed between Pt surface of Pt/C and transition metals such as Fe, Ni, Co, Cr, etc. The techniques reported for the preparation of carbon-supported Pt-based alloy catalysts include the traditional methods, such as impregnation 1,17 and precipitation. , These traditional methods have the disadvantage of particle sintering due to the high temperature (over 900 °C) required to form the alloy, resulting in a lower catalyst active area .…”

Section: Introductionmentioning

confidence: 99%

PtM/C Catalyst Prepared Using Reverse Micelle Method for Oxygen Reduction Reaction in PEM Fuel Cells

et al. 2008

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Synthesis of carbon-supported PtM/C catalysts (M ) Co, Cr, or Fe) using a new preparation technique, a reverse micelle method, is reported. The catalysts were characterized by different surface techniques: X-ray diffraction, scanning electron microscope, transmission electron microscope, and energy dispersive X-ray microanalysis. Surface characterization showed that Pt/M nanoparticles on catalysts were synthesized using the reverse micelle method. Pt/M nanoparticles were observed to be uniform spherical objects. The performance of the PtM/C catalysts was tested by the rotating disk electrode technique.

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2. Phosphoric acid fuel cells (PAFCs)

Cited by 44 publications

References 42 publications

An Investigation of Structure−Catalytic Activity Relationship for Pt−Co/C Bimetallic Nanoparticles toward the Oxygen Reduction Reaction

An Investigation of Structure−Catalytic Activity Relationship for Pt−Co/C Bimetallic Nanoparticles toward the Oxygen Reduction Reaction

Structure and Activity of Carbon-Supported Pt−Co Electrocatalysts for Oxygen Reduction

PtM/C Catalyst Prepared Using Reverse Micelle Method for Oxygen Reduction Reaction in PEM Fuel Cells

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