Distinction between Intermediates Produced in Main and Side Electrodic Reactions

Damjanović, A.; Genshaw, M. A.; Bockris, J. O'm.

doi:10.1063/1.1727457

Cited by 284 publications

(166 citation statements)

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“…Literature survey indicates that a simple reaction model 12 is consistent with many of the reported experimental results.…”

Section: Resultssupporting

confidence: 68%

Oxygen reduction at a manganate electrocatalyst in KOH solutions

Sequeira¹,

Santos²,

Baptista³

2006

J. Braz. Chem. Soc.

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A eletrocatálise da reação de redução do oxigênio por manganato de cálcio e lantânio, (La 0.5 Ca 0.5 MnO 3 ) (LCM), foi estudada por voltametria cíclica usando-se a técnica do eletrodo rotativo de disco e anel (RRDE) em meio alcalino. Os resultados do disco-anel e outros parâmetros cinéticos indicaram que, a baixas sobretensões, a redução do oxigênio ocorre por adsorção química. Para sobretensões mais elevadas foi observada a formação de peróxido de hidrogênio (HO 2 -neste caso) no eletrocatalisador. A densidade de corrente de permuta aparente, determinada para a redução do oxigênio no LCM foi de 5 × 10 -8 A cm -2, sendo o correspondente coeficiente de Tafel de 0,115 V por década. Discute-se e sugere-se um mecanismo para a reação de eletroredução do oxigênio.The electrocatalysis of the oxygen reduction reaction by lanthanum calcium manganate, (La 0.5 Ca 0.5 MnO 3 ) (LCM) has been studied by cyclic voltammetry using the rotating ring-disc electrode technique (RRDE) in alkaline medium. From the ring-disc data and other kinetic parameters it has been assumed that the oxygen reduction occurs by dissociative chemisorption at low overpotentials. At higher overpotentials, the formation of hydrogen peroxide (HO 2 -in this case) has been observed on this electrocatalyst. The apparent exchange current density value for oxygen reduction on LCM has been found to be 5 × 10 -8 A cm -2 , while the corresponding Tafel slope is 0.115 V per decade. The possible reaction mechanism for electroreduction of oxygen on this oxide catalyst has been discussed.

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“…Literature survey indicates that a simple reaction model 12 is consistent with many of the reported experimental results.…”

Section: Resultssupporting

confidence: 68%

Oxygen reduction at a manganate electrocatalyst in KOH solutions

Sequeira¹,

Santos²,

Baptista³

2006

J. Braz. Chem. Soc.

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“…In order to better illustrate the effect of the A-site on the ORR pathway, we estimated the phenomenological electron transfer rate constant for the four-electron step (k direct ) employing the Damjanovic model [15,[46][47][48][49]. Figure 6a, b contrast the value of k direct (0.65 V) as a function of the A-site ionic radius and the mean Mn-O bond length obtained from the EXAFS analysis (Table S3).…”

Section: Resultsmentioning

confidence: 99%

AMnO3 (A = Sr, La, Ca, Y) Perovskite Oxides as Oxygen Reduction Electrocatalysts

et al. 2018

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A series of perovskite-type manganites AMnO 3 (A = Sr, La, Ca and Y) particles were investigated as electrocatalysts for the oxygen reduction reaction. AMnO 3 materials were synthesized by means of an ionic-liquid method, yielding phase pure particles at different temperatures. Depending on the calcination temperature, particles with mean diameter between 20 and 150 nm were obtained. Bulk versus surface composition and structure are probed by X-ray photoelectron spectroscopy and extended X-ray absorption fine structure. Electrochemical studies were performed on composite carbon-oxide electrodes in alkaline environment. The electrocatalytic activity is discussed in terms of the effective Mn oxidation state, A:Mn particle surface ratio and the Mn-O distances.

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“…Various kinetic models for ORR have been developed to understand the reaction pathways. The first model was developed by Damjanovic et al [8] following which Wroblowa et al [9], and Anastasijević et al [10,11], proposed extensive models.…”

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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Distinction between Intermediates Produced in Main and Side Electrodic Reactions

Cited by 284 publications

References 1 publication

Oxygen reduction at a manganate electrocatalyst in KOH solutions

Oxygen reduction at a manganate electrocatalyst in KOH solutions

AMnO3 (A = Sr, La, Ca, Y) Perovskite Oxides as Oxygen Reduction Electrocatalysts

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

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