Ultra-low loading of platinum in proton exchange membrane-based fuel cells: a brief review

Ganesan, Aristatil; Narayanasamy, Mani

doi:10.1007/s40243-019-0156-x

Cited by 65 publications

(36 citation statements)

References 95 publications

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“…Esses NC combinam vantagens comuns a outros sistemas, tais como lipossomas e nanopartículas poliméricas, incluindo a possibilidade de carrear fármacos de diferentes características em seu interior e, semelhante aos lipossomas e nanoemulsões, apresentam em sua composição excipientes lipídicos. 69 As nanopartículas lipídicas sólidas são nanoesferas compostas de um núcleo lipídico sólido. Assim como as nanopartículas poliméricas, a sua matriz sólida pode proteger eficientemente os ativos farmacêuticos contra a degradação química e proporcionar modificação dos perfis de liberação do fármaco.…”

Section: Nanopartículas Lipídicas Sólidas E Carreador Lipídico Nanoesunclassified

Abrindo a Caixa De Pandora Dos Nanomedicamentos: Há Realmente Muito Mais ‘Espaço Lá Embaixo

et al. 2020

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Limitations of conventional treatment and dosage forms prompted the investigation of novel approaches that combine efficacy, selectivity and fewer adverse effects. These are the main promises of nanomedicine, generally defined as the application of nanotechnology to the biomedical field. Despite the considerable advances over the years and the large number of publications resulting from the growth of nanomedicine, there are still many hurdles and unknown factors limiting its successful translation from promise to reality. These factors range from the lack of standardization in the terminology and regulations, to the lack of understanding of interactions between nanocarriers and the biological system, and their influence on drug pharmacodynamics. In this manuscript, we aim at presenting and discussing concepts and terminologies used in the nanomedicine field and examining the main types of nanocarriers and their effects to modulate biological barriers and aid drug transport, bioavailability and targeting.

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Section: Nanopartículas Lipídicas Sólidas E Carreador Lipídico Nanoesunclassified

Abrindo a Caixa De Pandora Dos Nanomedicamentos: Há Realmente Muito Mais ‘Espaço Lá Embaixo

et al. 2020

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“…As a solution, increasing platinum (Pt) catalyst loading can accelerate the reaction, but limitations in scalability and economic feasibility restrict engineering of high Pt loading. As a result, numerous studies on PEMFCs have focused on development of optimized catalyst coated membranes (CCM) and MEA layout with high catalyst utilization applying strategies such as (i) increasing Pt loading [3][4][5], and (ii) graded catalyst loading [6,7]. Yet, fulfilling the Department of Energy (DOE) targets is an ongoing endeavor [8].…”

Section: Introductionmentioning

confidence: 99%

On the State and Stability of Fuel Cell Catalyst Inks

Bapat

Giehl²,

Kohsakowski³

et al. 2021

Preprint

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Catalyst layers (CL) as an active component of the catalyst coated membrane (CCM) form the heart of proton electrolyte membrane fuel cells (PEMFC). For optimum performance of the fuel cell, obtaining suitable structural and functional characteristics for the CL is crucial. Direct tuning of the microstructure and morphology of the CL is non-trivial; hence catalyst inks as catalyst layer precursors need to be modulated, which are then applied onto a membrane, to form the CCM. Obtaining favorable dispersion characteristics forms an important prerequisite in engineering catalyst inks for large scale manufacturing. In order to facilitate a knowledge-based approach for developing fuel cell inks, this work introduces new tools and methods to study both the dispersion state and stability characteristics, simultaneously. Catalyst inks were prepared using different processing methods which include stirring and ultrasonication. The proposed tools are used to characterize and elucidate the effects of the processing method. Structural characterization of the dispersed particles and their assemblages was carried out by means of transmission electron microscopy. Analytical centrifugation (AC) was used to study the state and stability of inks. Herein, we introduce new concepts, S score and stability trajectory, for a time-resolved assessment of inks in their native state using AC. The findings were validated and rationalized using transmittograms as a direct visualization technique. The flowability of inks was investigated by rheological measurements. It was found that probe sonication only up to an optimum amplitude leads to a highly stable colloidal ink.

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“…For instance, in References efficient PEMFC anodes were prepared with 14 to 22 μg Pt cm −2 ; our research group has recently reported highly efficient HOR catalysts with only a few μg cm −2 of the noble metal . However, in majority of currently used PEMFC systems the Pt loadings in anode catalysts capable of practically usable lifetimes are in the range of 0.2 to 0.5 mg cm −2 ; further reduction of Pt content often leads to issues of limited durability or mass transport limitations . No long‐term durability tests under heavy‐duty operation conditions have been presented so far for the anodes with extremely low (μg cm −2 range) platinum contents, which is the aim of the present study.…”

Section: Introductionmentioning

confidence: 99%

“…5 Despite of development of noble metal free electrodes (using, for example, nickel nitrides, 6 cobalt, 7 nickel-copper alloys, 8 metal [oxy] sulfides, 9 or even metal-free carbon catalysts 10 ) the Ptbased catalysts still remain the most efficient and most widely used catalytic elements for PEMFC. 11 Another strategy is thus a development of materials with almost negligible amounts of highly dispersed noble metal particles [11][12][13][14] or their alloying with other cheaper metals, 15,16 which may reach the industrial requirements for sustainable and affordable FC systems. In PEMFC the kinetics of hydrogen oxidation reaction (HOR) is significantly faster than that of oxygen reduction reaction (ORR).…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, this noble metal is listed by the European Commission as a critical raw material; its resources are limited and expected to be depleted by the end of the 21st century regardless of the introduction of the FC vehicles . Despite of development of noble metal free electrodes (using, for example, nickel nitrides, cobalt, nickel‐copper alloys, metal [oxy]sulfides, or even metal‐free carbon catalysts) the Pt‐based catalysts still remain the most efficient and most widely used catalytic elements for PEMFC . Another strategy is thus a development of materials with almost negligible amounts of highly dispersed noble metal particles or their alloying with other cheaper metals, which may reach the industrial requirements for sustainable and affordable FC systems.…”

Section: Introductionmentioning

confidence: 99%

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Durable ultra‐low‐platinum ionomer‐free anode catalyst for hydrogen proton exchange membrane fuel cell

et al. 2020

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Summary An ultra‐low‐platinum catalyst based on finely dispersed platinum (Pt) deposited on a highly porous complex microporous layer was investigated as a candidate of durable anode catalyst for hydrogen oxidation reaction (HOR) in proton exchange membrane fuel cells. Etching of teflonated and nitridized base carbon substrate in oxygen plasma and simultaneous deposition of cerium oxide were applied to increase active surface area and electrochemical activity of the platinum nanocatalyst. Ultra‐low loadings of Pt (between 0.85 and 8.5 μg cm−2) deposited by magnetron sputtering on this substrate were assembled with Nafion 212 membrane and commercially available Pt/C cathodes (300‐400 μg cm−2 Pt). Such membrane electrode assembly (MEA) with extremely low Pt content at anode can deliver high output power densities, reaching 0.95 W cm−2 or 0.65 W cm−2 with only 1.7 μg cm−2 of Pt, using H2 as fuel and pure O2 or air as an oxidant, respectively. Although electrocatalysts with highly dispersed active metals are known to often suffer from irreversible degradation, the above MEAs proved to be very stable when the cell was subjected to a durability test under heavy duty conditions of on/off cycling. The system with lower Pt content is more prone to water flooding which can, however, be eliminated by maintaining better control over the fuel humidity. Average decay of the cell voltage less than 50 μV h−1 was obtained in the cycling regime, while excellent stability <10 μV h−1 is achievable under the static load of 0.4 A cm−2.

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Ultra-low loading of platinum in proton exchange membrane-based fuel cells: a brief review

Cited by 65 publications

References 95 publications

Abrindo a Caixa De Pandora Dos Nanomedicamentos: Há Realmente Muito Mais ‘Espaço Lá Embaixo

Abrindo a Caixa De Pandora Dos Nanomedicamentos: Há Realmente Muito Mais ‘Espaço Lá Embaixo

On the State and Stability of Fuel Cell Catalyst Inks

Durable ultra‐low‐platinum ionomer‐free anode catalyst for hydrogen proton exchange membrane fuel cell

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