How does α-FePc catalysts dispersed onto high specific surface carbon support work towards oxygen reduction reaction (orr)?

Baranton, Stève; Coutanceau, Christophe; Garnier, Emmanuel; Léger, Jean‐Michel

doi:10.1016/j.jelechem.2006.03.007

Cited by 98 publications

(79 citation statements)

References 52 publications

(94 reference statements)

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“…The total number of exchanged electrons during the ORR on the FePc/C catalyst was detected close to 3.9 -4 by rotating ring-disk electrode experiments. Furthermore, the same authors found that FePc converts from α-phase to β-phase after heat treatment and the α-phase displays an overpotential towards ORR 100 mV lower than the β-phase [130].…”

Section: Co-and Fe-based Phthalocyanines (Pc)mentioning

confidence: 91%

Nonprecious metal catalysts for the molecular oxygen‐reduction reaction

Feng

Alonso-Vante

2008

Physica Status Solidi (b)

174

109

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This review covers the electrocatalytic activities, the corresponding influence factors and the synthesis methods of nonprecious‐metal electrocatalysts towards oxygen‐reduction reaction (ORR) for fuel‐cell systems. In particular, the chalcogenides and the macrocycles containing Co or Fe metals have been focused upon. Due to the scarcity of Pt metal, the Co‐ and Fe‐based chalcogenides are potentially interesting substitutes of Pt although they still show lower catalytic activities for ORR and lower electrochemical and chemical stability in the present fuel‐cell electrolytes. Compared to Pt electrocatalysts, the Co‐ and Fe‐based macrocycles, such as TMPP, TPP, Pc and TAA, are among the most promising substitutes for Pt because of their comparable catalytic activities towards ORR and the higher insensitivity to methanol (in direct methanol fuel cells – DMFC) although they still have some drawbacks, namely lower stability and shorter durability. Novel catalyst synthesis methods, modification techniques of catalysts as well as supporting substrates are expected to be developed in the future to satisfy the requirements of commercial fuel cells. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Co-and Fe-based Phthalocyanines (Pc)mentioning

confidence: 91%

Nonprecious metal catalysts for the molecular oxygen‐reduction reaction

Feng

Alonso-Vante

2008

Physica Status Solidi (b)

174

109

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“…Non-noble metal catalysts based on chalcogenides [36][37][38][39] and macrocycles of transition metals [40][41][42][43][44] have shown good activity for the ORR. However these materials did not yet match the catalytic activity of dispersed platinum.…”

Section: Ii2 New Preparation Methods Of Efficient Electrode Catalystsmentioning

confidence: 99%

Do not forget the electrochemical characteristics of the membrane electrode assembly when designing a Proton Exchange Membrane Fuel Cell stack

Lamy

Jones

Coutanceau

et al. 2011

Electrochimica Acta

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International audienceThe membrane electrode assembly (MEA) is the key component of a PEMFC stack. Conventional MEAs are composed of catalyzed electrodes loaded with 0.1-0.4 mgPt cm−2 pressed against a Nafion® membrane, leading to cell performance close to 0.8 W cm−2 at 0.6 V. Due to their limited stability at high temperatures, the cost of platinum catalysts and that of proton exchange membranes, the recycling problems and material availability, the MEA components do not match the requirements for large scale development of PEMCFs at a low cost, particularly for automotive applications. Novel approaches to medium and high temperature membranes are described in this work, and a composite polybenzimidazole-poly(vinylphosphonic) acid membrane, stable up to 190 ◦C, led to a power density of 0.5 W cm−2 at 160 ◦C under 3 bar abs with hydrogen and air. Concerning the preparation of efficient electrocatalysts supported on a Vulcan XC72 carbon powder, the Bönnemann colloidal method and above all plasma sputtering allowed preparing bimetallic platinum-based electrocatalysts with a low Pt loading. In the case of plasma deposition of Pt nanoclusters, Pt loadings as low as 10 g cm−2 were achieved, leading to a very high mass power density of ca. 20 kW g−1 Pt . Finally characterization of the MEA electrical properties by Electrochemical Impedance Spectroscopy (EIS) based on a theoretical model of mass and charge transport inside the active and gas diffusion layers, together with the optimization of the operating parameters (cell temperature, humidity, flow rate and pressure) allowed obtaining electrical performance greater than 1.2 W cm−2 using an homemade MEA with a rather low Pt loading

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“…For example, a co-facial structure (Fig. 11.15) of the macrocycles with a metal -metal distance close to 0.4 nm seems to improve the electroactivity with regard to oxygen reduction as well as the selectivity with regard to water formation via a four-electron process [Collman et al, 1980;Baranton et al, 2006].…”

Section: Electrocatalytic Aspects Of Oxygen Reductionmentioning

confidence: 99%

“…The explanation for the existence of two Tafel slopes is somewhat different at a-FePc; however, different adsorption modes of molecular oxygen are certainly involved. One explanation could be the capability of a-FePc to form both PcFe -O 2 -FePc m-oxo species, allowing breaking of the O -O bond, and FePc -O 2 peroxo species [Baranton et al, 2006]. The difference in catalytic behavior between the two forms of FePc crystals can then be explained by the catalyst structure.…”

Section: Electrocatalytic Aspects Of Oxygen Reductionmentioning

confidence: 99%