Is nitrogen important in the formulation of Fe-based catalysts for oxygen reduction in solid polymer fuel cells?

Lalande, G.; Côté, R.; Guay, Daniel; Dodelet, J. P.; Weng, Lt.; Bertrand, Patrick

doi:10.1016/s0013-4686(96)00361-1

Cited by 217 publications

(201 citation statements)

References 36 publications

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“…In 1989, Gupta et al showed that the combination of metal acetate with polyacrylonitrile and carbon black leads to the formation of active materials when pyrolysed at temperatures >600 • C [3]. Main efforts to find suitable nitrogen and metal precursors were made by Dodelet's group and others [4][5][6][7]. These early approaches were strongly limited in the density of active sites, as the carbon black always displays a relative mass in the final catalyst that is not contributing in terms of active sites [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Structure-Forming Agent on the Performance of Fe-N-C Catalysts

et al. 2018

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Abstract:In this work, the influence of the structure-forming agent on the composition, morphology and oxygen reduction reaction (ORR) activity of Fe-N-C catalysts was investigated. As structure-forming agents (SFAs), dicyandiamide (DCDA) (nitrogen source) or oxalic acid (oxygen source) or mixtures thereof were used. For characterization, cyclic voltammetry and rotating disc electrode (RDE) experiments were performed in 0.1 M H 2 SO 4 . In addition to this, N 2 sorption measurements and Raman spectroscopy were performed for the structural, and elemental analysis for chemical characterization. The role of metal, nitrogen and carbon sources within the synthesis of Fe-N-C catalysts has been pointed out before. Here, we show that the optimum in terms of ORR activity is achieved if both N-and O-containing SFAs are used in almost similar fractions. All catalysts display a redox couple, where its position depends on the fractions of SFAs. The SFA has also a strong impact on the morphology: Catalysts that were prepared with a larger fraction of N-containing SFA revealed a higher order in graphitization, indicated by bands in the 2nd order range of the Raman spectra. Nevertheless, the optimum in terms of ORR activity is obtained for the catalyst with highest D/G band ratio. Therefore, the results indicate that the presence of an additional oxygen-containing SFA is beneficial within the preparation.

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Section: Introductionmentioning

confidence: 99%

Influence of the Structure-Forming Agent on the Performance of Fe-N-C Catalysts

et al. 2018

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“…The nature of the active site (obtained after heat treatment) in terms of its location on the carbon support (edge versus basal plane) [22], coordination number (Fe-N 4 versus non-Fe-N 4 environment) [23], and chemical identity of the nitrogen functional groups (pyridinic, pyrrolic, and quaternary) [24] have remained a key aspect of intense discussion. Several theories exist to explain the nature of the active site such as those proposed by van Veen et al [25][26][27], McBreen et al [28], Schulenburg et al [29], Yeager et al [2,30], Scherson et al [31][32][33], and Dodelet et al [22,[34][35][36][37][38][39][40][41][42][43][44][45]. Although some authors observed that ORR is conducted by sites comprised of surface nitrogen groups devoid of any metal ion centers [46,47], it is now widely accepted that the transition-metal ion centers coordinated to four nitrogen groups (Me-N 4 ) on graphitic surfaces constitute the active site [22,23,30,48], whereas chelation primarily serves to prevent the metal center from passivation/corrosion under electrochemical conditions [49].…”

Section: Introductionmentioning

confidence: 99%

Fundamental Mechanistic Understanding of Electrocatalysis of Oxygen Reduction on Pt and Non-Pt Surfaces: Acid versus Alkaline Media

Ramaswamy

Mukerjee

2012

Advances in Physical Chemistry

339

255

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Complex electrochemical reactions such as Oxygen Reduction Reaction (ORR) involving multi-electron transfer is an electrocatalytic inner-sphere electron transfer process that exhibit strong dependence on the nature of the electrode surface. This criterion (along with required stability in acidic electrolytes) has largely limited ORR catalysts to the platinum-based surfaces. New evidence in alkaline media, discussed here, throws light on the involvement of surface-independent outer-sphere electron transfer component in the overall electrocatalytic process. This surface non-specificity gives rise to the possibility of using a wide-range of non-noble metal surfaces as electrode materials for ORR in alkaline media. However, this outer-sphere process predominantly leads only to peroxide intermediate as the final product. The importance of promoting the electrocatalytic inner-sphere electron transfer by facilitation of direct adsorption of molecular oxygen on the active site is emphasized by using pyrolyzed metal porphyrins as electrocatalysts. A comparison of ORR reaction mechanisms between acidic and alkaline conditions is elucidated here. The primary advantage of performing ORR in alkaline media is found to be the enhanced activation of the peroxide intermediate on the active site that enables the complete four-electron transfer. ORR reaction schemes involving both outer-and inner-sphere electron transfer mechanisms are proposed.

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“…3 Carbon-nitrogen materials prepared in other ways can be inactive toward oxygen reduction. Lalande et al 4 reported that CN x particles prepared by pyrolysis of nitrogen-containing organic compounds in Ar at 1000°C or by pyrolysis of a hydrocarbon, followed by heat treatment in NH 3 at 1000°C, did not show any activity toward oxygen reduction.…”

Section: Introductionmentioning

confidence: 99%

O₂ Reduction on Graphite and Nitrogen-Doped Graphite: Experiment and Theory

Sidik¹,

Anderson²,

Subramanian³

et al. 2006

J. Phys. Chem. B

607

488

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An experimental and theoretical study of electroreduction of oxygen to hydrogen peroxide is presented. The experimental measurements of nitrided Ketjenblack indicated an onset potential for reduction of approximately 0.5 V (SHE) compared to the onset potential of 0.2 V observed for untreated carbon. Quantum calculations on cluster models of nitrided and un-nitrided graphite sheets show that carbon radical sites formed adjacent to substitutional N in graphite are active for O 2 electroreduction to H 2 O 2 via and adsorbed OOH intermediate. The weak catalytic effect of untreated carbon is attributed to weaker bonding of OOH to the H atom-terminated graphite edges. Substitutional N atoms that are far from graphite sheet edges will be active, and those that are close to the edges will be less active. Interference from electrochemical reduction of H atoms on the reactive sites is considered, and it is shown that in the potential range of H 2 O 2 formation the reactive sites are not blocked by adsorbed H atoms.

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Is nitrogen important in the formulation of Fe-based catalysts for oxygen reduction in solid polymer fuel cells?

Cited by 217 publications

References 36 publications

Influence of the Structure-Forming Agent on the Performance of Fe-N-C Catalysts

Influence of the Structure-Forming Agent on the Performance of Fe-N-C Catalysts

Fundamental Mechanistic Understanding of Electrocatalysis of Oxygen Reduction on Pt and Non-Pt Surfaces: Acid versus Alkaline Media

O₂ Reduction on Graphite and Nitrogen-Doped Graphite: Experiment and Theory

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Is nitrogen important in the formulation of Fe-based catalysts for oxygen reduction in solid polymer fuel cells?

Cited by 217 publications

References 36 publications

Influence of the Structure-Forming Agent on the Performance of Fe-N-C Catalysts

Influence of the Structure-Forming Agent on the Performance of Fe-N-C Catalysts

Fundamental Mechanistic Understanding of Electrocatalysis of Oxygen Reduction on Pt and Non-Pt Surfaces: Acid versus Alkaline Media

O2 Reduction on Graphite and Nitrogen-Doped Graphite: Experiment and Theory

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O₂ Reduction on Graphite and Nitrogen-Doped Graphite: Experiment and Theory