Graphitic Carbon as Durable Cathode‐Catalyst Support for PEFCs

Selvaganesh, S. Vinod; Selvarani, G.; Sridhar, P.; Pitchumani, S.; Shukla, A. K.

doi:10.1002/fuce.201000151

Cited by 39 publications

(41 citation statements)

References 48 publications

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“…This increase in the capacitive current in the CV curve may be attributed to the surface roughening initiated by the surface defects [55,56]. Similar increase in capacitive current was already observed in our previous study, were carbon corrosion occurred along with increase in capacitance [57]. On the contrary, for the PEFC comprising Pt/TNW and Pt/TWCNT (figure not included) cathode, the increase in capacitance value is comparatively smaller both prior and after AST which indicates stability of MWCNT support against oxidation due to the presence of TiO 2 nanowires.…”

Section: Resultssupporting

confidence: 87%

TiO2-nanowire/MWCNT composite with enhanced performance and durability for polymer electrolyte fuel cells

Selvaganesh¹,

Dhanasekaran²,

Bhat³

2017

Electrochemical Energy Technology

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Durability is a major issue and has been the growing focus of research for the commercialization of polymer electrolyte fuel cells (PEFCs). Corrosion of carbon support is a key parameter as it triggers the Pt catalyst degradation and affects cell performance, which in turn affects the longevity of the cells. Herein, we describe a hybrid composite support of TiO 2 -nanowires and Multiwalled carbon nanotubes (MWCNTs) that offers resistance to corrosion under stressful operating conditions. Titania nanowires which have been shown to be more efficient and catalytically active than spherically shaped TiO 2 . TiO 2 -MWCNT composites are prepared through a hydrothermal method, followed by Pt deposition using a polyol method. Crystal structure, morphology, and oxidation state are examined through various characterization techniques. Electrochemical performance of TiO 2 -nanowire/MWCNT composite-supported Pt at various ratios of TiO 2 /MWCNT is assessed in PEFCs. Pt on support with optimum composition of TiO 2 -nanowires to MWCNTs exhibits fuel cell performance superior to Pt on MWCNTs. Accelerated stress testing (AST) between 1 and 1.5 V reveals that the designed catalyst on nanocomposite support possesses superior electrochemical activity and shows only 16% loss in catalytic activity in relation to 35% for Pt/MWCNTs even after 6000 potential cycles. Subsequently, the samples were characterized after AST to correlate the loss in fuel cell performance

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Section: Resultssupporting

confidence: 87%

TiO2-nanowire/MWCNT composite with enhanced performance and durability for polymer electrolyte fuel cells

Selvaganesh¹,

Dhanasekaran²,

Bhat³

2017

Electrochemical Energy Technology

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“…4,5,10 Carbon supports with a high degree of graphitization (e.g. steam etched carbon blacks, 23,24 graphitic carbon blacks, 13,25,26 graphitized multiwall carbon nanotubes (MWCNTs), 27,28 graphitic carbon nanocages (CNCs), 29,30 nanographite, 31 and graphitized mesoporous carbon (MC) 32 ) show improved stability in relation to non-graphitized carbon supports when subjected to accelerated stress tests (ASTs). Besides these studies that employed high-temperature (>2500…”

mentioning

confidence: 99%

Polybenzimidazole (PBI) Functionalized Nanographene as Highly Stable Catalyst Support for Polymer Electrolyte Membrane Fuel Cells (PEMFCs)

Xin

Yang

Qiu

et al. 2016

J. Electrochem. Soc.

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Nanoscale graphenes were used as cathode catalyst supports in proton exchange membrane fuel cells (PEMFCs). Surface-initiated polymerization that covalently bonds polybenzimidazole (PBI) polymer on the surface of graphene supports enables the uniform distribution of the Pt nanoparticles, as well as allows the sealing of the unterminated carbon bonds usually present on the edge of graphene from the chemical reduction of graphene oxide. The nanographene effectively shortens the length of channels and pores for O 2 diffusion/water dissipation and significantly increases the primary pore volume. Further addition of p-phenyl sulfonic functional graphitic carbon particles as spacers, increases the specific volume of the secondary pores and greatly improves O 2 mass transport within the catalyst layers. The developed composite cathode catalyst of Pt/PBI-nanographene (50 wt%) + SO 3 H-graphitic carbon black demonstrates a higher beginning of life (BOL) PEMFC performance as compared to both Pt/PBI-nanographene (50 wt%) and Pt/PBI-graphene (50 wt%) + SO 3 H-graphitic carbon black (GCB). Accelerated stress tests show excellent support durability compared to that of traditional Pt/Vulcan XC72 catalysts, when subjected to 10,000 cycles from 1.0 V to 1.5 V. This study suggests the promise of using PBI-nanographene + SO 3 H-GCB hybrid supports in fuel cells to achieve the 2020 DOE targets for transportation applications. High stability is required for polymer electrolyte membrane fuel cells (PEMFCs) catalyst supports because they play a critical role in determining the overall durability of PEMFC systems.1 Carbon-based supports have been widely used to support Pt or Pt alloy catalysts in PEMFCs.2 High-surface-area carbon (HSAC) supports minimize the aggregation of the catalyst nanoparticles as HSAC provides more sites for catalyst to nucleate than low-surface-area-carbon (LSAC), thereby avoiding forming big aggregates. Thus, it increases the Pt utilization that leads to more active electro-catalysts with low platinum loadings (< 0.1 mg-Pt/cm 2 ), 2 yet HSAC is vulnerable for corrosion due to the increased surface area. Good electrical conductivity of the carbon materials provides good electron transport.3 In addition, the random aggregates of the primary carbon particles help the distribution of ionomer to access the active sites during the fabrication of membrane electrode assemblies (MEA), and also allow the construction of a highly porous catalyst layer that enables O 2 diffusion and the water dissipation in PEMFCs. The most commonly used carbon blacks in low temperature PEMFCs include Vulcan XC72 (Cabot Corp., USA), Black Pearls 2000 (Cabot Corp., USA) Ketjen Black EC300j (AkzoNobel Corp., the Netherlands), Ketjen Black EC600 (AkzoNobel Corp., the Netherlands), etc. These carbon blacks consist of inhomogeneous graphitic structures and amorphous carbons. 4 The small size of the graphitic domains cause a high density of edge sites, (particularly in the case of high BET (Brunauer-Emmett-Teller) surface area carbon supports), ...

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“…In addition to the unsatisfactory ORR activity, there are also problems associated with performance loss with long term operation due to aggregation and dissolution of Pt particles and carbon corrosion [2][3][4][5][6][7]. Consequently, the activity and durability of Pt/C catalysts must both be improved for wide-spread commercialization of polymer electrolyte fuel cells [1,8].…”

Section: Introductionmentioning

confidence: 99%

Improving oxygen reduction reaction activity and durability of 1.5nm Pt by addition of ruthenium oxide nanosheets

Takimoto

Chauvin

Sugimoto

2013

Electrochemistry Communications

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The durability of commercial carbon supported Pt nanoparticles with average particle size of 1.5 nm (20 mass% Pt/C) has been improved by the addition of ruthenium oxide nanosheets (RuO2ns) without sacrificing the initial activity towards oxygen reduction reaction.The initial oxygen reduction reaction activity of the composite catalyst was slightly higher than as-received Pt/C. The electrocatalytic activity after consecutive potential cycling tests of the composite catalyst was c.a. 1.3 times higher than non-modified Pt/C. The increased durability of the composite catalyst is attributed to the improved preservation of the electrochemically active Pt surface area with the addition of ruthenium oxide.

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Graphitic Carbon as Durable Cathode‐Catalyst Support for PEFCs

Cited by 39 publications

References 48 publications

TiO2-nanowire/MWCNT composite with enhanced performance and durability for polymer electrolyte fuel cells

TiO2-nanowire/MWCNT composite with enhanced performance and durability for polymer electrolyte fuel cells

Polybenzimidazole (PBI) Functionalized Nanographene as Highly Stable Catalyst Support for Polymer Electrolyte Membrane Fuel Cells (PEMFCs)

Improving oxygen reduction reaction activity and durability of 1.5nm Pt by addition of ruthenium oxide nanosheets

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