Phosphoric Acid Fuel Cells (PAFCs) for Utilities: Electrocatalyst Crystallite Design, Carbon Support, and Matrix Materials Challenges

Stonehart, P.; Wheeler, D.

doi:10.1007/0-387-25838-8_4

Cited by 14 publications

(5 citation statements)

References 36 publications

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“…30 The BET surface area of GH900 was found to be 279 AE 3 m 2 g À1 , a value that is 17 times higher than that of GH710 particles and comparable to that of other carbon materials suitable as electrocatalyst supports. 31 These results indicate that microspheres develop a pore structure upon annealing; this is consistent with the rough surface observed via SEM and with the observation of a solid core via FIB, which could develop without a signicant decrease in microsphere diameter only if accompanied by an increase in porosity.…”

supporting

confidence: 86%

Template-free ultraspray pyrolysis synthesis of N/Fe-doped carbon microspheres for oxygen reduction electrocatalysis

et al. 2015

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Ultrasonic spray pyrolysis was used in a continuous flow apparatus for the template-free synthesis of ironand nitrogen-doped porous carbon materials. Solutions of glucose, histidine and Fe(CH 3 COO) 2 were nebulized and pyrolyzed yielding carbon microspheres. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Focused Ion Beam (FIB) milling revealed that microspheres initially possess empty cores and a smooth shell. Further annealing leads to a collapse of this shell, and formation of porous microspheres with high roughness and iron-rich aggregates. X-ray Diffraction (XRD) and Photoelectron Spectroscopy (XPS) were used to investigate bulk and surface chemistry: microspheres were found to undergo graphitization; Fe and Fe 3 C particles form and become encapsulated within the carbon phase, while the nitrogen present in the precursor solution results in the formation of pyridinic/pyrrolic N-centers. The microspheres were tested as electrocatalysts for the oxygen reduction reaction (ORR) in acidic solution. Polarization curves using a Rotating Disk Electrode (RDE) yielded electrocatalytic behavior, and the number of exchanged electrons n ¼ 3.7 AE 0.2 calculated from Koutecky-Levich plots suggests that direct formation of H 2 O is the preferred ORR mechanism.These results indicate that this synthetic approach offers a simple and scalable strategy for the preparation of electrode materials for polymer electrolyte membrane fuel cells.

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supporting

confidence: 86%

Template-free ultraspray pyrolysis synthesis of N/Fe-doped carbon microspheres for oxygen reduction electrocatalysis

et al. 2015

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“…Stonehart and Wheeler 17 and Popov et al 7 correlated the current densities on the microelectrodes, taking into account the change of concentration around them, with the current density on the macroelectrode. This is because the charge transfer occurs on the microelectrodes, while the mass-transfer limitations are related to the diffusion layer of the macroelectrode.…”

Section: Micro-and Macroelectrodesmentioning

confidence: 99%

The Effect of Morphology of Activated Electrodes on Their Electrochemical Activity

Popov

Živković

Nikolić

2010

Modern Aspects of Electrochemistry

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“…Graphitic multi-wall CNTs are chosen as conductive framework for the support and offer several benefits over traditional carbon black [ 9,10 ]. Namely, they have a better long range order which decreases the carbon corrosion kinetics through reduced defect concentration on their surfaces where initiation occurs [ 11,12 ]. CNT also have strong mechanical properties which can prevent structure collapse, exhibit suitable charge transfer, and other ideal transport properties for products and reactants [ 13,14 ].…”

Section: Introductionmentioning

confidence: 99%

Composite Carbon Nanotube and Titania Catalyst Supports for Enhanced Activity and Durability

2013

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In polymer electrolyte cells, an approach is shown for construction of resilient electrocatalysts. In the anode where the hydrogen oxidation reaction is subject to poisoning from fuel impurities like carbon monoxide (CO), increased tolerance and stability for the catalyst is revealed by modification of the support structure and properties. A carbon nanotube framework serves as the foundation for metal oxide addition, namely titania and niobium doped form. The corrosion resistant transition metal oxides form a strong bond with platinum catalysts through unique electronic interactions, measured by XPS. Several other material characterizations are also included to make comparisons between composites. Composite supports contribute improved reactivity towards oxidation of CO, especially in reduced titania. Carbon corrosion resistance is also measured and shown to be the greatest for this support. Synergistic combination of effects is observed directly by preparation of electrocatalysts into working membrane electrode assemblies measured for their performance & durability.

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Phosphoric Acid Fuel Cells (PAFCs) for Utilities: Electrocatalyst Crystallite Design, Carbon Support, and Matrix Materials Challenges

Cited by 14 publications

References 36 publications

Template-free ultraspray pyrolysis synthesis of N/Fe-doped carbon microspheres for oxygen reduction electrocatalysis

Template-free ultraspray pyrolysis synthesis of N/Fe-doped carbon microspheres for oxygen reduction electrocatalysis

The Effect of Morphology of Activated Electrodes on Their Electrochemical Activity

Composite Carbon Nanotube and Titania Catalyst Supports for Enhanced Activity and Durability

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