Electrocatalytic activity of metal phthalocyanines for oxygen reduction

Zagal, José H.; Páez, Maritza; Tanaka, Auro Atsushi; Santos, José Ribeiro dos; Linkous, Clovis A.

doi:10.1016/0022-0728(92)80442-7

Cited by 300 publications

(248 citation statements)

References 37 publications

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“…In Figure 4c the potentials related to the peak maxima in the anodic sweep of the cyclic voltammograms are given as a function of the ratio of oxalic acid in the SFA. Roughly, the trend is similar as for the kinetic current density: The resulting kinetic current density was getting as higher as more positive the anodic peak position was, what is in agreement with previous reports [30][31][32]. Nevertheless, it becomes clear, that E (Peakanode) is only a weak activity descriptor for this group of catalysts.…”

Section: Resultssupporting

confidence: 91%

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: Resultssupporting

confidence: 91%

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

et al. 2018

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“…These curves were analyzed according to the characteristics of a first-order irreversible reaction controlled by diffusion, where the current I (A) is given by the Koutecky-Levich equation: 21,38 Figure 4B for a fixed potencial of -0.25 V. Parallel lines were also observed for other potentials, which indicates a first order kinetics with respect to hydrazine in solution and a constant value of n over the potential range investigated. A value of n ca.…”

Section: Rotating Disk Electrode Measurementsmentioning

confidence: 93%

“…These curves were analyzed according to the characteristics of a first-order irreversible reaction controlled by diffusion, where the current I (A) is given by the Koutecky-Levich equation: 21,38 ( 5) where I K (A) and I D (A) represents the kinetic and diffusion controlled currents, respectively, with (6) where D 0 is the diffusion coefficient (D N 2 H 4 = 1.4×10 -5 cm 2 s -1 ), 37 C 0 the reactant concentration in the bulk solution (C N 2 H 4 = 5.0×10 -3 mol L -1 ), n the solution kinematic viscosity (n=1.02×10 -2 cm 2 s -1 , 37,41,43 A the electrode geometrical area (A OPG = 0.4 cm 2 ), n the number of electrons transferred/reactant molecule, f is the electrode rotation rate in radians s -1 and the other terms have their usual meanings. According to equations 5 and 6, a plot of I -1 vs. f -1/2 (Koutecky-Levich plot) should be linear with an angular coefficient of 1/B, as shown in Figure 4B for a fixed potencial of -0.25 V. Parallel lines were also observed for other potentials, which indicates a first order kinetics with respect to hydrazine in solution and a constant value of n over the potential range investigated.…”

Section: Rotating Disk Electrode Measurementsmentioning

confidence: 99%

“…The redox potential M(II)/(I) has been found to be an important reactivity index for these complexes 20,21,34,35,40,[46][47][48][49] so it is interesting to compare the catalytic activity of FeTPyPz with that of similar complexes like iron phthalocyanines and derivatives using the redox potential. In previous studies, it has been observed that the electrocatalytic activity, measured as current (at constant potential) divided by the surface concentration of catalyst and plotted versus the Fe(II)/(I) redox potential of the complex gives a volcano-shaped curve.…”

Section: Rotating Disk Electrode Measurementsmentioning

confidence: 99%

“…Similar assignments have been also made for a glassy carbon electrode modified with iron tetraaminophthalocyanine and several substituted iron phthalocyanines adsorbed on OPG. 21,35,37 In order to establish an immersion time for modification of the OPG surface with FeTPyPz, the charge associated with the voltammetric peak 2 was plotted versus the immersion time (t/min) of the electrode surface in the FeTPyPz solution. Figure 1B shows that immersion time higher than 5 min is sufficient to reach the maximum charge value associated with FeTPyPz adsorbed species.…”

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Electrocatalytic oxidation of hydrazine in alkaline media promoted by iron tetrapyridinoporphyrazine adsorbed on graphite surface

Dantas¹,

Reis²,

Tanaka³

et al. 2008

J. Braz. Chem. Soc.

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A oxidação eletrocatalítica de hidrazina foi estudada sobre um eletrodo de grafite pirolítico ordinário modificado com tetrapiridinoporfirazina de ferro (FeTPyPz) com as técnicas de voltametria cíclica e de eletrodo de disco rotatório. Análise dos voltamogramas registrados a diferentes velocidades de varredura do potencial e das curvas de polarização para diferentes velocidades de rotação do eletrodo mostraram que a reação de eletroxidação de hidrazina sobre FeTPyPz processa-se de acordo com um mecanismo envolvendo 4 elétrons e com a formação de N 2 como principal produto. Os parâmetros cinéticos sugerem que a segunda etapa de transferência de carga é a etapa determinante da velocidade da reação. A atividade eletrocatalítica do complexo FeTPyPz depende do potencial formal do processo redox Fe(II)/Fe(I), que apresentou bom ajuste num gráfico do tipo vulcano formado por diferentes ftalocianinas de ferro, indicando que este potencial formal é um bom indicador da reatividade destes complexos.The electrocatalytic oxidation of hydrazine was studied using an ordinary pyrolytic graphite electrode modified with iron tetrapyridinoporphyrazine complex (FeTPyPz), employing cyclic voltammetry and rotating disk electrode techniques. Analyses of the voltammograms recorded at different potential scan rates and the polarization curves at different electrode rotation rates showed that the reaction of electrooxidation of hydrazine on FeTPyPz occurs via 4-electrons with the formation of N 2 as main product. The kinetic parameters suggest that the second electron transfer step is rate controlling. The activity of FeTPyPz depends on its Fe(II)/Fe(I) formal potential and fits well in a volcano plot that includes several iron phthalocyanines, indicating that such formal potential is a good reactivity index for these complexes.Keywords: hydrazine oxidation, modified graphite electrode, iron tetrapyridinoporphyrazine, volcano plot IntroductionThe study of chemically modified electrodes has attracted considerable interest in the last decades as researchers attempt to exert more control over the chemical nature of the electrode surface. Molecules of known reactivity are then incorporated or confined on the electrode surface, acting as mediators for electron transfer reactions. Applications include electrocatalysis, electroanalysis, sensors and biosensors, as well as in electrochemical detection systems used in flow-injection analysis or high performance liquid chromatography. One applicability of these electrodes refers to the oxidation and detection of hydrazine, an important chemical compound used in jet and rocket fuels and in the production of agricultural and textile chemicals, drugs, explosives, photographic developers, blowing agents used in the manufacture of foam rubber, and in the prevention of rusting in boilers and nuclear reactors. 31 Furthermore, the detection of hydrazine and its derivatives is very important in pharmacology due to the recognition as carcinogenic and hepatotoxic substances. 31,32 In order to reduce the typi...

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Charge Transfer of Tetraphenylporphyrin Zinc Complexes Incorporated in a Poly(2-vinylpyridine) Matrix

Zhang

Abe

Kaneko

1998

J. Porphyrins Phthalocyanines

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An indium tin oxide (ITO) electrode was coated by a poly(2-vinylpyridine) (P-2VP) film incorporating tetraphenylporphyrin zinc ( ZnTPP ) as a redox center. A cyclic voltammogram (CV) exhibited a couple of redox waves at 0.7 V (vs Ag / AgCl ). The potential-step chronoamperospectrometry (PSCAS) measurement was carried out on the modified electrode immersed in a 0.1 M LiClO 4 aqueous solution at pH 3.5 under argon atmosphere. Assuming a random distribution of the redox species in the macromolecular structure, the charge transfer distance between the adjacent ZnTPP complexes was obtained as 1.08 nm. The charge hopping distance between the redox centers (1.01 nm) and the bounded motion distance (0.07 nm after 2h) were obtained according to their different response time in the electrochemical measurement. Considering the contributions from both the charge hopping and bounded motion, the second order rate constant of electron hopping was 4.1 × 104 M−1s−1.

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Electrocatalytic activity of metal phthalocyanines for oxygen reduction

Cited by 300 publications

References 37 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

Electrocatalytic oxidation of hydrazine in alkaline media promoted by iron tetrapyridinoporphyrazine adsorbed on graphite surface

Charge Transfer of Tetraphenylporphyrin Zinc Complexes Incorporated in a Poly(2-vinylpyridine) Matrix

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