Electrocatalysis of the oxygen reduction process on metal chelates in acid electrolyte

Bagotzky, V.S.; Tarasevich, M. R.; Radyushkina, K. A.; Левина, О. А.; Andrusyova, S.I.

doi:10.1016/0378-7753(78)85014-9

Cited by 245 publications

(109 citation statements)

References 6 publications

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“…The most widely adopted "ex situ" technique used to study the ORR performance of such ECs is cyclic voltammetry using a rotating (ring) disk electrode. 18,19 Since 1994 some authors have also succeeded in testing CN-based ECs in single fuel cell configuration.…”

Section: F Uel Cells (Fcs) Operating At Low Temperatures (T < 200 °C)mentioning

confidence: 99%

Origins, Developments, and Perspectives of Carbon Nitride-Based Electrocatalysts for Application in Low-Temperature FCs

et al. 2015

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F uel cells (FCs) operating at low temperatures (T < 200 °C)show several very attractive features, including: (a) relatively simple assembly; (b) good compatibility with the environment; and (c) very high efficiency with respect to internal combustion engines. However, the full potential of low-temperature FCs can only be achieved by addressing a number of crucial issues involved in their operation. One of the most important bottlenecks is represented by the slow kinetics of the oxygen reduction reaction (ORR).1 Typical examples of low-temperature fuel cells include proton exchange membrane fuel cells (PEMFCs) and anion-exchange membrane fuel cells (AEMFCs).1 To achieve energy conversion efficiencies and power densities compatible with applications, all these devices require suitable ORR electrocatalysts (ECs) to minimize cathode polarization losses.Ideally, ORR ECs should possess the following features: a) Active sites capable of the highest turnover frequency at the lowest overpotentials; b) A large active surface area, maximizing the number of active sites; c) A morphology that facilitates the efficient transport of reactants and products to and from the active sites; d) High electron conductivity, to minimize ohmic losses; e) A high dielectric environment to aid the ion exchange processes between the active sites and the ion-conducting membrane; f) High stability under operating conditions, to achieve high durability.To comply with these requirements, state-of-the-art ORR ECs consist of Pt-nanocrystals supported on conductive carbon nanoparticles (NPs) that possess a spherical morphology and a large surface area 2 (indicated as "Pt/C ref. ECs"). These systems are characterized by a high dispersion of the ORR active sites, which are easily accessible by the reactants. Their performance is comparable to that of pristine "Pt-black" ECs, but with a reduced loading of precious metal. However, the large-scale rollout of FC technology employing Pt/C ref. ECs is hindered by their insufficient durability and very high costs."Carbon nitride-based electrocatalysts" (CN-based ECs) have shown great promise to address the issues outlined above. CN-based ECs are composed of a carbon-based matrix embedding nitrogen atoms. The matrix coordinates metal-based species, including: (a) NPs of metals (e.g., Pt, Pd), metal alloys (e.g., PtNi x , PdCo y Ni z ), oxides (e.g., Fe 3 O 4 ) or carbides (e.g., FeC x ); or (b) coordination complexes of single metal atoms (e.g., Fe, Co).3 There are two main driving forces behind the development of CN-based ECs. CN-based ECs including Pt-group elements (PGMs) show very high ORR activity and a remarkable tolerance towards the oxidizing conditions typical at the cathodes of low-temperature FCs. 4 The carbon nitride (CN) matrix embeds the various inorganic NPs in "nitrogen coordination nests". 5These strong interactions inhibit the main mechanisms involved in the long-term degradation of typical Pt/C ref. ECs, especially particle agglomeration and particle detachment from the support.

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Section: F Uel Cells (Fcs) Operating At Low Temperatures (T < 200 °C)mentioning

confidence: 99%

Origins, Developments, and Perspectives of Carbon Nitride-Based Electrocatalysts for Application in Low-Temperature FCs

et al. 2015

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“…It is clear that they can be prepared from any kind of metal, nitrogen and carbon precursor, but that the overall achievable activity will be strongly related to the optimization of the mixtures. In the first approaches, macrocycles were supported on a carbon black and then pyrolysed at temperatures above 600 • C to form significantly more active catalysts in comparison to the non-pyrolysed macrocycles [1,2]. To enable cheaper preparation and independent optimization of metal and nitrogen content in the synthesis, alternative preparation approaches had to be established.…”

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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“…The results were published in References [273,276]. The influence of cobalt phthalocyanine, tetraphenylporphyrin, and tetrabenzoporphyrin increased noticeably after heat treatment.…”

Section: Vladimir Sergeevich During Ielan Period and In His Former Iementioning

confidence: 54%

V. S. Bagotsky’s contribution to modern electrochemistry

Скундин

Tsirlina

2014

J Solid State Electrochem

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Electrocatalysis of the oxygen reduction process on metal chelates in acid electrolyte

Cited by 245 publications

References 6 publications

Origins, Developments, and Perspectives of Carbon Nitride-Based Electrocatalysts for Application in Low-Temperature FCs

Origins, Developments, and Perspectives of Carbon Nitride-Based Electrocatalysts for Application in Low-Temperature FCs

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

V. S. Bagotsky’s contribution to modern electrochemistry

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