Rotating disk electrodes

Opekar, František; Béran, P.

doi:10.1016/s0022-0728(76)80129-5

Cited by 202 publications

(65 citation statements)

References 440 publications

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“…Such a plot from the results obtained (Figure 4) shows two segments, a sloping one (I) and a horizontal one (11). The slope of segment I is close to -11118 mV for l a , l b , and l c , which is the expected value for an activation controlled reaction, but close to -11200 mV for l c and Id.…”

Section: Discussionmentioning

confidence: 61%

Electrochemically induced homogeneous electron transfer to aromatic disulfides

1981

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Contributed in honour of the 70th Birthday of Professor L. Horner.The rate constant of the heterogeneous electron transfer from a platinum electrode to aromatic disulfides is low, whereas the homogeneous electron transfer from suitable aromatic anion radicals is much faster. Anion radicals of such aromatic compounds can thus be generated electrochemically at potentials more negative than the normal standard reduction potential of the disulfide, but less negative than its observed reduction potential. An attempt is made to estimate E, of the aromatic disulfides from the rates of the homogeneous electron transfer from a number of donors and the reversible redox potential of these donors. Elektrochemisch induzierte, homogene Elektroneniibertragung auf aromatische DisulfideDie Geschwindigkeitskonstante der heterogenen Elektroneniibertragung von einer Platinelektrode auf aromatische Disulfide ist klein, wahrend die homogene Elektroneniibertragung von geeigneten aromatischen Radikalanionen wesentlich rascher stattfindet . Derartige Radikalanionen von aromatischen Verbindungen kBnnen elektrochemisch bei Potentialen erhalten werden, die zwar negativer als das Standard-Reduktionspotential des Disulfids, aber nicht negativer als die beobachteten Reduktionspotentiale der Disulfide sind. Es wird der Versuch unternommen, Eo-Werte von aromatischen Disulfiden aus den Geschwindigkeiten homogener Elektroneniibertragungen durch einige Donoren und den reversiblen Redoxpotentialen dieser Donoren zu ermitteln.Electrochemical measurements of organic sulfur compounds at mercury electrodes are in many cases complicated by the formation of mercury compounds before orland during the electrochemical reaction'). The polarographic half-wave potentials for the reduction of disulfides and oxidation of mercaptans are influenced by reactions with mercury and do not allow the measurement of the redox potentials of these systems by this method.Cyclic voltammetric peak potentials (E,) of aromatic disulfides depend strongly on the electrode material as illustrated in Figure 1, showing cyclic voltammetric (CV)curves of bis(4chlorophenyl) disulfide in N,N-dimethylformamide/tetrabutylammonium iodide (DMF/TBAI) at vitreous carbon, platinum, and copper electrodes. The systems are irreversible at all sweep rates ( u ) accessible at present ( v < 103V s-l) even at vitreous carbon which has the highest heterogeneous rate constant of all three Liebigs Ann. Chem. 1981

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Section: Discussionmentioning

confidence: 61%

Electrochemically induced homogeneous electron transfer to aromatic disulfides

1981

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“…118 The influence of mass transport on the ORR kinetics at high overpotentials while rotating result in a well-defined mass-transport-limiting current (Fig. 9a), which can be tuned by the rotation speed based on the Levich equation.…”

Section: The Three-electrode Electrochemical Cellmentioning

confidence: 99%

Toward the rational design of non-precious transition metal oxides for oxygen electrocatalysis

Hong

Risch

Stoerzinger

et al. 2015

Energy Environ. Sci.

1,767

1,491

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REVIEWThis journal is © The Royal Society of Chemistry 2013 J. Name., 2013, 00, 1-3 | 1 In this Review, we discuss the state-of-the-art understanding of non-precious transition metal oxides that catalyze the oxygen reduction and evolution reactions. Understanding and mastering the kinetics of oxygen electrocatalysis is instrumental to making use of photosynthesis, advancing solar fuels, fuel cells, electrolyzers, and metal-air batteries. We first present key insights, assumptions and limitations of well-known activity descriptors and reaction mechanisms in the past four decades. The turnover frequency of crystalline oxides as promising catalysts is also put into perspective with amorphous oxides and photosystem II. Particular attention is paid to electronic structure parameters that can potentially govern the adsorbate binding strength and thus provide simple rationales and design principles to predict new catalyst chemistries with enhanced activity. We share new perspective synthesizing mechanism and electronic descriptors developed from both molecular orbital and solid state band structure principles. We conclude with an outlook on the opportunities in future research within this rapidly developing field. Broader ContextThe formation of chemical bonds is an energy dense mode of storing energy. In both nature and technology, the electrochemical generation and consumption of fuels is one of the most efficient routes for energy usage. Solar and electrical energy can be stored in chemical bonds by splitting water or metal oxides to produce hydrogen and metal. These compounds can then be oxidized to produce energy when coupled to the reduction of oxygen. However, these device efficiencies are severely limited by the catalysis of oxygen electrochemical processes -namely the oxygen reduction reaction and oxygen evolution reaction, which have slow kinetics. Non-precious transition metal oxides show promise as cost-effective substitutes for noble metals in commercially viable renewable energy storage and conversion devices. Furthermore, this class of materials has ben efitted from a wealth of spectroscopic and first-principles studies in the past few decades, providing the frameworks and theories needed to understand the electronic structure and design optimal catalysts. The incredibly diverse range of chemistries and physical properties that can be explored in oxide families afford numerous degrees of freedom for conducting systematic investigations relating intrinsic mat erial properties to catalytic performance. Here, we present background on the fundamental concepts in catalysis for the rational design of transition metal perovskite oxide catalysts for oxygen electrocatalysis and critically examine the current understanding a nd its impact on future directions of perovskite catalysts.

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“…Os eletrodos disco rotatório pertencem ao grupo dos eletrodos hidrodinâmicos, onde há o transporte de massa na sua superfície e, consequentemente, a magnitude da corrente durante as reações no eletrodo é controlada por convecção das espécies eletroativas, causada pela rotação do eletrodo ou por agitação da solução (OPEKAR & BERAN, 1975).…”

Section: Caracterização E Modelagem Do Problemaunclassified

Simulação CFD do escoamento em uma célula eletroquímica de teste de corrosão utilizando o software OpenFOAM

Maioli¹,

Maioli²,

Martins³

2014

Anais Do v Encontro Científico De Física Aplicada

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ResumoCom o avanço da tecnologia dos computadores e capacidade de processamento, os softwares de CFD estão ficando cada vez mais poderosos e versáteis. Os softwares mais desenvolvidos e utilizados são os comercias, como Ansys CFX e FLUENT, porém apresentam custos relativamente altos para a obtenção de licenças. O trabalho apresenta um estudo do escoamento em uma célula eletroquímica de teste de corrosão contendo um eletrodo disco rotatório, utilizando o software gratuito OpenFOAM, para servir de alternativa aos softwares comerciais. O principal problema encontrado foi a difícil convergência da solução ao se refinar a malha em torno do rotor. Isso foi contornado simulando primeiro para uma malha mais grossa, depois em uma um pouco mais refinada com esquema de discretização de primeira ordem, e, por fim, alterando para um esquema de segunda ordem para melhorar a precisão, obtendo bons resultados condizentes com a teoria.

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Rotating disk electrodes

Cited by 202 publications

References 440 publications

Electrochemically induced homogeneous electron transfer to aromatic disulfides

Electrochemically induced homogeneous electron transfer to aromatic disulfides

Toward the rational design of non-precious transition metal oxides for oxygen electrocatalysis

Simulação CFD do escoamento em uma célula eletroquímica de teste de corrosão utilizando o software OpenFOAM

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