Effect of temperature in cerium-ion-catalyzed bromate-driven oscillators

Nagy, Gabriella; Kőrös, E.; Oftedal, Norunn; Tjelflaat, Kjetil; Ruoff, Peter

doi:10.1016/0009-2614(96)00023-1

Cited by 35 publications

(42 citation statements)

References 21 publications

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“…Indeed, periods of 95 and 5 s were observed at 25 and 5°C, respectively. For the time window shown, the number of potential oscillations is 48,19,11,8, and 3 at 5, 10, 15, 20, and 25°C, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Although the authors recognized the important role of adding flow to a closed system to achieve temperature compensation, 48 the impact of the flow rate on the oscillation amplitude was not presented. Studies of the hydrogen peroxide/thiosulfate/sulfite flow system 32 revealed that, in general, the oscillation amplitude decreases gradually with increasing temperature.…”

Section: Resultsmentioning

confidence: 99%

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Temperature (Over)Compensation in an Oscillatory Surface Reaction

et al. 2008

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Biological rhythms are regulated by homeostatic mechanisms that assure that physiological clocks function reliably independent of temperature changes in the environment. Temperature compensation, the independence of the oscillatory period on temperature, is known to play a central role in many biological rhythms, but it is rather rare in chemical oscillators. We study the influence of temperature on the oscillatory dynamics during the catalytic oxidation of formic acid on a polycrystalline platinum electrode. The experiments are performed at five temperatures from 5 to 25°C, and the oscillations are studied under galvanostatic control. Under oscillatory conditions, only non-Arrhenius behavior is observed. Overcompensation with temperature coefficient (q 10 , defined as the ratio between the rate constants at temperature T + 10°C and at T) < 1 is found in most cases, except that temperature compensation with q 10 ≈ 1 predominates at high applied currents. The behavior of the period and the amplitude result from a complex interplay between temperature and applied current or, equivalently, the distance from thermodynamic equilibrium. High, positive apparent activation energies were obtained under voltammetric, nonoscillatory conditions, which implies that the non-Arrhenius behavior observed under oscillatory conditions results from the interplay among reaction steps rather than from a weak temperature dependence of the individual steps.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Temperature (Over)Compensation in an Oscillatory Surface Reaction

et al. 2008

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“…The Ce(III)/Ce(IV) redox couple also participates in the Belousov-Zhabotinsky oscillating reaction via autocatalytic oxidation [229,230]. Efforts have been devoted to further study the effects and kinetics of cerium in such complex reaction mechanisms [231][232][233][234][235], including the reaction mechanism with malonic acid [236,237].…”

Section: Other Applicationsmentioning

confidence: 99%

Electrochemical redox processes involving soluble cerium species

Arenas

León

Walsh

2016

Electrochimica Acta

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Anodic oxidation of cerous ions and cathodic reduction of ceric ions, in aqueous acidic solutions, play an important role in electrochemical processes at laboratory and industrial scale. Ceric ions, which have been used for oxidation of organic wastes and off-gases in environmental treatment, are a wellestablished oxidant for indirect organic synthesis and specialised cleaning processes, including oxide film removal from tanks and process pipework in nuclear decontamination. They also provide a classical reagent for chemical analysis in the laboratory. The reversible oxidation of cerous ions is an important reaction in the positive compartment of various redox flow batteries during charge and discharge cycling. A knowledge of the thermodynamics and kinetics of the redox reaction is critical to an understanding of the role of cerium redox species in these applications. Suitable choices of electrode material (metal or ceramic; coated or uncoated), geometry/structure (2-or 3-dimensional) and electrolyte flow conditions (hence an acceptable mass transport rate) are critical to achieving effective electrocatalysis, a high performance and a long lifetime. This review considers the electrochemistry of soluble cerium species and their diverse uses in electrochemical technology, especially for redox flow batteries and mediated electrochemical oxidation.

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“…A Figura 3 mostra o período oscilatório em função da temperatura nos três sistemas estudados. Inicialmente percebe-se que os sistemas estudados passam mais tempo oscilando que os demais sistemas BZ encontrados na literatura, 20,21,24,31 até mesmo quando comparados a um sistema de igual composição e concentração inicial. 12 A segunda observação a ser feita refere-se à considerável diferença encontrada entre os valores de τ osc para o S 1 e o sistema de igual composição, concentração e condições experimentais relatado na literatura.…”

Section: Período Oscilatóriounclassified

“…Embora o efeito da temperatura tenha sido estudado em vários sistemas BZ, o trabalho realizado por Nagy et al 24 foi o primeiro a mostrar que a energia de ativação global é significativamente dependente do sistema BZ e de sua composição. Deve-se notar, no entanto, que no caso de mecanismos complexos, é difícil associar a energia de ativação obtida a uma única etapa do processo global.…”

Section: Introductionunclassified

Dinâmica oscilatória em sistemas contendo bromato e 1,4-ciclo-hexanodiona em meio ácido: I. Efeito da temperatura

Oliveira¹,

Oliveira²,

Varela³

2012

Quím. Nova

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Recebido em 16/5/11; aceito em 11/8/11; publicado na web em 30/9/11 OSCILLATORY DYNAMICS IN SYSTEMS CONTAINING BROMATE AND 1,4-CYCLOHEXANEDIONE IN ACIDIC MEDIA. I. THE EFFECT OF TEMPERATURE. We present in this work the influence of temperature on the dynamics of homogeneous chemical systems containing bromate and 1,4-cyclohexanedione (1,4-CHD) in acidic media. In particular, the following systems were studied: bromate/1,4-CHD/acid, bromate/1,4-CHD/ferroin/acid and bromate/1,4-CHD/trisbipyridine ruthenium/acid. Investigations were carried out by means of an electrochemical probe, at five temperatures between 5 and 45 °C. Activation energies (E a ) were estimated in different ways for the pre-oscillatory and oscillatory regimes. In any case, the E a was found to depend on the catalyst, composition and initial concentrations. In addition, it was observed that ferroin and trisbipyridine ruthenium act as catalysts only during the transition between the induction period and oscillatory regime.Keywords: oscillations; complex kinetics; 1,4-cyclohexanedione. INTRODUÇÃOUma das principais características dos sistemas vivos é a presença de ritmos nas funções regulatórias, exemplos incluem processos em diferentes níveis como os ritmos circadianos, batimentos cardíacos, ciclo menstrual, ciclo de Krebs e outros ciclos intracelulares, como a glicólise. Fenômenos desta natureza são normalmente referidos como processos de auto-organização temporal e também ocorrem em várias reações químicas na forma de oscilações nas concentrações de espécies intermediárias. Em sistemas abertos, o regime oscilatório pode persistir indefinidamente, desde que a alimentação de reagentes frescos e a remoção de produtos formados ocorram de forma adequada. Em sistemas fechados, por outro lado, as oscilações ocorrem de forma transiente e cessam quando a diminuição dos reagentes move o sistema para fora da bacia de atração referente ao estado oscilatório. Adicionalmente aos processos auto-organizados em domínio temporal, o transporte de espécies, fundamentalmente via difusão, pode cooperar com as etapas químicas envolvidas e em determinadas circunstâncias levar à formação de estruturas espaço-temporais. 1 A auto-organização dinâmica ocorre em diversos sistemas físico-químicos abertos e afastados do estado de equilíbrio e vem se tornando uma área de intensa pesquisa. 2 Indubitavelmente, os osciladores homogêneos baseados na redução de bromato são os mais estudados. 3 A origem destes osciladores se deu na Rússia, em 1951, quando Boris Pavlovich Belousov, interessado no ciclo de Krebs, estudava a reação entre bromato e ácido cítrico em meio ácido com íons cério Ce(IV). Belousov esperava observar uma mudança na coloração da solução de amarelo para incolor, como resultado da redução do Ce(IV) para Ce(III). Em lugar de uma simples transição, a solução mudou de cor do amarelo para o incolor por diversas vezes. Belousov só conseguiu publicar sua descoberta em 1958, em um periódico bem pouco conhecido. Em 1961, Anatol M. Zhabotinskii deu continuidade ao trabalho ...

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Effect of temperature in cerium-ion-catalyzed bromate-driven oscillators

Cited by 35 publications

References 21 publications

Temperature (Over)Compensation in an Oscillatory Surface Reaction

Temperature (Over)Compensation in an Oscillatory Surface Reaction

Electrochemical redox processes involving soluble cerium species

Dinâmica oscilatória em sistemas contendo bromato e 1,4-ciclo-hexanodiona em meio ácido: I. Efeito da temperatura

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