Alternative supports for the preparation of catalysts for low-temperature fuel cells: the use of carbon nanotubes

Carmo, Marcelo; Paganin, Valdecir Antonio; Rosolen, José Maurício; González, Ernesto Rafael

doi:10.1016/j.jpowsour.2004.10.023

Cited by 253 publications

(125 citation statements)

References 21 publications

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“…In the catalyst layers of PEMFCs, platinum nanoparticles are always dispersed on supports to increase the active area and thereby lower material costs [84][85][86]. As concluded in Ref.…”

Section: Carbon Oxidationmentioning

confidence: 97%

A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes: Causes, consequences, and mitigation strategies

Wang

et al. 2012

Journal of Power Sources

253

147

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a b s t r a c tPerformance degradation during startup and shutdown is considered an important issue affecting the durability and lifetime of proton exchange membrane fuel cells (PEMFCs). Due to the high potentials experienced by the cathode during startup and shutdown, the conventional carbon support for the cathode catalyst is prone to oxidation by reacting with oxygen or water. This paper presents an overview of the causes and consequences of performance degradation after frequent startup-shutdown cycles. Mitigation strategies are also summarized, including the use of novel catalyst supports and the application of system strategies to prevent performance degradation in PEMFCs. It is found from the literature review that improvements in catalyst supports to prevent oxidation come at the expense of high cost, and the novel supports developed to date are not sufficient to completely prevent carbon oxidation in fuel cell engines. System strategies, including potential control and reaction gas control, have been developed and applied in fuel cell engines to alleviate or even avoid performance decay. This review aims to provide a clear understanding of the mechanisms related to degradation behaviors during the startup and shutdown processes, thereby helping fuel cell material or system developers in their efforts to prevent performance degradation and prolong the lifetime of PEMFCs.Crown

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“…In the catalyst layers of PEMFCs, platinum nanoparticles are always dispersed on supports to increase the active area and thereby lower material costs [84][85][86]. As concluded in Ref.…”

Section: Carbon Oxidationmentioning

confidence: 97%

A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes: Causes, consequences, and mitigation strategies

Wang

et al. 2012

Journal of Power Sources

253

147

View full text Add to dashboard Cite

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“…Thus catalysts can show high electrocatalytic activity if they have a large surface area. Carbon nanotubes (CNTs) possess some important features including large surface area, low resistance, high stability, 13 …”

Section: −12mentioning

confidence: 99%

Enhanced electrocatalytic efficiency of C/MWNTs for methanol oxidation using Ni deposited on MWNTs

Farsak¹,

Kardaş²

2015

Turk J Chem

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Abstract:The power density of direct methanol fuel cells (DMFCs) can be changed by using different anode materials.Especially porous materials are preferred for the anode. In the present study, multiwall carbon nanotubes were first injected into graphite. Then, by depositing nickel, a catalyst was prepared for use as the anode material of the DMFC.This catalyst was named Ni@MWNTs. The oxidation of methanol and some kinetic parameters were investigated in KOH solution. Cyclic voltammetry was used for the electrochemical measurements. Kinetic parameters of the methanol oxidation were determined at different temperatures, scan rates, and concentrations of methanol. The surface morphologies and nickel deposition amounts of the Ni@MWNTs and Ni-C (nickel deposited graphite) electrodes were characterized with scanning electron microscope (SEM), atomic force microscope (AFM), and energy-dispersive X-ray (EDX) spectroscope. It was found that the Ni@MWNTs electrode was more active than the Ni-C electrode. The activation energy of the Ni@MWNTs electrode was calculated as 19.52 kJ mol −1 for the methanol oxidation process.

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“…Although many of these alternative supports have been tested in DMFC [103][104][105][106][107][108][109][110][111][112][113][114][115][116][117], their long-term stability in DMFC conditions has not been studied widely though it is a significant reason for their research [33,118]. In light of this, Vulcan-, GNF-and FWCNT-PtRu were tested for a period of 3 days in a micro-DMFC anode in Publication IV.…”

Section: The Role Of Carbon Supportmentioning

confidence: 99%

“…However, this has not been widely investigated in the literature (Publications II, III and IV) [33,107,117] as most studies of different catalyst supports in a DMFC only report the performance [103][104][105][106][108][109][110][111][112][113][114][115][116]. In Publication IV, three…”

Section: Carbon Supportsmentioning

confidence: 99%

Silicon nanograss as micro fuel cell gas diffusion layer

et al. 2010

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Direct methanol fuel cells (DMFC) produce electrical energy directly from chemical energy. They are a promising candidate for power sources of portable devices due to the high energy density of methanol and the quick recharging procedure by fuel insertion. However, the problem areas of the DMFC are the slow electro-oxidation of methanol and the permeated methanol reacting at the cathode. New catalysts are constantly searched but they are often tested only for catalytic activity and the DMFC testing is omitted even though the catalyst layer (CL) structure has a large impact on the performance. Miniaturization of the system is also necessary for portable applications. Silicon etching can be used to fabricate small structures for fuel cells replacing or enhancing the functions of laboratory-scale components.In the first part of this thesis, new catalysts for the DMFC are studied with the emphasis on the CL structure. Different carbon supports for the anode were studied: standard carbon black and alternative few-walled carbon nanotubes (FWCNT) and graphitized carbon nanofiber (GNF). The alternative supports showed better DMFC performance but their stability was lower than with carbon black. However, the CL formed with GNF showed a very porous structure enhancing the mass transfer, so that higher binder content could be used improving the stability to the level of carbon black and the performance by 30%. The FWCNTs were also investigated as a platform for enzymatic methanol oxidation by studying the electrochemical properties of an immobilized cofactor pyrroloquinoline quinone (PQQ). A large amount of PQQ was adsorbed having a strong redox response and good stability in a wide pH window. For the cathode, a methanol-tolerant, Pt-free nitrogen-doped FWCNTs were tested in an alkaline DMFC as such testing is not often made. Its performance was remarkably 4 times better than with Pt when synthetic air was used as the oxidant.In the second part of thesis, an integrated gas diffusion layer (GDL) consisting of Si nanoneedles (nanograss) was tested in a micro fuel cell (MFC). The layer functioned properly at low current densities. For high power applications, a standard carbon cloth GDL was tested with the nanograss as a contact surface reducing the resistance between the GDL and the flow field. The use of the nanograss improved the MFC performance and stability. Finally, the MFCs were used as a catalyst testing platform and the results were compared with a similar test in a laboratory-scale DMFC. The results varied showing that the DMFC components also have a large impact on catalyst testing.Keywords direct methanol fuel cell, carbon nanomaterials, micro fuel cells, catalyst layer Tiivistelmä Suorametanolipolttokennot (SMPK) tuottavat sähköenergiaa suoraan kemiallisesta energiasta. Ne ovat lupaava vaihtoehto kannettavien laitteiden voimanlähteeksi, koska metanolilla on korkea energiatiheys ja lataaminen tapahtuu nopeasti polttoainelisäyksellä. SMPK:lla on kuitenkin rajoitteina metanolin hidas hapetusreaktio ja katodi...

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Alternative supports for the preparation of catalysts for low-temperature fuel cells: the use of carbon nanotubes

Cited by 253 publications

References 21 publications

A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes: Causes, consequences, and mitigation strategies

A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes: Causes, consequences, and mitigation strategies

Enhanced electrocatalytic efficiency of C/MWNTs for methanol oxidation using Ni deposited on MWNTs

Silicon nanograss as micro fuel cell gas diffusion layer

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