Electrocatalysts for O2 reduction

Yeager, Ernest

doi:10.1016/0013-4686(84)85006-9

Cited by 1,201 publications

(845 citation statements)

References 36 publications

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“…Emissions like NO x and SO 2 are prevented because of the low temperature at which the BES operates. The oxygen reduction reaction can follow two overall pathways: (1) the direct four-electron pathway in which oxygen is reduced to water or hydroxide and (2) the peroxide pathway (Yeager 1983). The oxygen reduction reactions via the two pathways are:…”

Section: Overpotentials For Oxygen Reductionmentioning

confidence: 99%

New applications and performance of bioelectrochemical systems

Hamelers

Heijne

Sleutels

et al. 2009

Appl Microbiol Biotechnol

255

134

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Bioelectrochemical systems (BESs) are emerging technologies which use microorganisms to catalyze the reactions at the anode and/or cathode. BES research is advancing rapidly, and a whole range of applications using different electron donors and acceptors has already been developed. In this mini review, we focus on technological aspects of the expanding application of BESs. We will analyze the anode and cathode half-reactions in terms of their standard and actual potential and report the overpotentials of these half-reactions by comparing the reported potentials with their theoretical potentials. When combining anodes with cathodes in a BES, new bottlenecks and opportunities arise. For application of BESs, it is crucial to lower the internal energy losses and increase productivity at the same time. Membranes are a crucial element to obtain high efficiencies and pure products but increase the internal resistance of BESs. The comparison between production of fuels and chemicals in BESs and in present production processes should gain more attention in future BES research. By making this comparison, it will become clear if the scope of BESs can and should be further developed into the field of biorefineries.

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Section: Overpotentials For Oxygen Reductionmentioning

confidence: 99%

New applications and performance of bioelectrochemical systems

Hamelers

Heijne

Sleutels

et al. 2009

Appl Microbiol Biotechnol

255

134

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“…Esta transformação química ocorre segundo dois mecanismos globais bastante discutidos na literatura: o mecanismo direto (4 elétrons, Figura 1 -I) e, o mecanismo de formação do peróxido (2 elétrons). 4,5 A distinção entre os dois mecanismos torna-se difícil pelo fato da redução direta também poder envolver a formação de peróxido, desde que este permaneça adsorvido na superfície do eletrodo sem sofrer dessorção ou decomposição, e a sua redução ocorra subsequentemente. Este processo também envolve 4 elétrons, porém é chamado de mecanismo em série (Figura 1 -II).…”

Section: Introductionunclassified

Reaproveitamento de óxidos de manganês de pilhas descartadas para eletrocatálise da reação de redução de oxigênio em meio básico

Rascio¹,

Souza²,

Neto³

et al. 2010

Quím. Nova

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Recebido em 12/3/09; aceito em 6/10/09; publicado na web em 2/3/10 USE OF MANGANESE OXIDES RECOVERED FROM SPENT BATTERIES IN ELECTROCATALYSIS OF OXYGEN REDUCTION REACTION IN ALKALINE MEDIUM. The oxygen reduction reaction was studied in alkaline media using manganese oxides obtained from spent batteries as electrocatalysts. Three processes were used to recover manganese oxides from spent batteries. The particles obtained were in the range from 8 to 11 nm. The electrochemical experiments indicated a good electrocatalytic activity toward oxygen reduction using the different samples and showing approximately a direct transference of 4 electrons during the process. Even though all the processes were efficient, the best result was observed for the prepared sample using reactants of low cost.Keywords: manganese oxide; oxygen reduction; battery metal recovery. INTRODUÇÃOVários dispositivos que são utilizados no dia a dia, como máquinas térmicas, motores de combustão interna, caldeiras industriais, dentre outras, utilizam combustíveis de origem fóssil como fonte de energia. A utilização deste tipo não renovável de energia produz grandes quantidades de poluentes, destacando-se CO 2 , CO, NO x , SO x , hidrocarbonetos e materiais particulados, que são responsáveis por boa parte dos problemas ambientais, tais como o efeito estufa e a chuva ácida.Com o crescente avanço da tecnologia surgiu também nos últi-mos anos uma grande necessidade por fontes portáteis de energia. No Brasil são produzidas anualmente cerca de 3 bilhões de unidades de pilhas e baterias para suprir esta necessidade.1 Segundo dados da ABINEE (Associação Brasileira da Indústria Eletroeletrônica) a porcentagem de pilhas alcalinas vendidas no Brasil representa cerca de 30% do total das vendas no mercado. Em contrapartida, as pilhas alcalinas dominam o mercado nos EUA por durarem cerca de seis vezes mais que as pilhas de zinco-carvão. 1As pilhas citadas acima após seu esgotamento energético são descartadas, tendo por destinos finais locais inadequados. Isto causa grandes impactos ambientais, principalmente relacionados à poluição de lençóis freáticos pela contaminação de metais pesados como o manganês, reconhecidamente um dos principais componentes deste tipo de pilha. 2Este metal, presente na forma de óxidos nas pilhas, pode ser recuperado e empregado no uso e desenvolvimento de células a combustível como eletrocatalisador para a reação de redução do oxigênio. Esta reação impõe grandes limitações para o desenvolvimento de células a combustível, 3 que são uma boa opção na substituição das atuais fontes de energia, podendo satisfazer tanto as necessidades energéticas supridas pelos combustíveis fósseis como para aplicação em dispositivos portáteis que utilizam pilhas e baterias.A reação de redução de oxigênio (RRO) é uma reação multieletrônica que inclui algumas etapas elementares em seu mecanismo. Esta transformação química ocorre segundo dois mecanismos globais bastante discutidos na literatura: o mecanismo direto (4 elétrons, Figura 1 -I) e, o mecanismo de fo...

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“…As mentioned previously, two reaction mechanisms have been proposed for this reaction: a two-electron mechanism and a four-electron mechanism. On the basis of previously reported results, 22,24 we chose the four-electron mechanism as the main mechanism, and assumed there are four reaction steps.…”

Section: A Oxygen Reduction Reaction On the Pt(111) Surfacementioning

confidence: 99%

“…20,21 Several researchers have shown that a four-electron mechanism and a two-electron mechanism are the main reaction mechanisms. [22][23][24][25] When the Pt catalyst is sufficiently pure, the four-electron reaction mechanism is considered to be the main mechanism both in acidic media and in alkaline media. 22 Research result by cyclic voltammetry has also shown that the four-electron reaction mechanism is operative in alkaline medium.…”

mentioning

confidence: 99%

“…[22][23][24][25] When the Pt catalyst is sufficiently pure, the four-electron reaction mechanism is considered to be the main mechanism both in acidic media and in alkaline media. 22 Research result by cyclic voltammetry has also shown that the four-electron reaction mechanism is operative in alkaline medium. 23 Miah and Ohsaka 24 deemed the four-electron mechanism to be the main oxygen reduction reaction mechanism, whereas Markovic et al 25 considered the two-electron reaction mechanism to be operative.…”

mentioning

confidence: 99%

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Oxygen reduction on a Pt(111) catalyst in HT-PEM fuel cells by density functional theory

Sun

Almheiri

et al. 2017

AIP Advances

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On the mechanism of carbon nanostructures formation at reaction of organic compounds at high pressure and temperature AIP Advances 7, 085101 (2017) The oxygen reduction reaction plays an important role in the performance of hightemperature proton exchange membrane (HT-PEM) fuel cells. In this study, a molecular dynamics model, which is based on the density functional theory and couples the system's energy, the exchange-correlation energy functional, the charge density distribution function, and the simplified Kohn-Sham equation, was developed to simulate the oxygen reduction reaction on a Pt(111) surface. Additionally, an electrochemical reaction system on the basis of a four-electron reaction mechanism was also developed for this simulation. The reaction path of the oxygen reduction reaction, the product structure of each reaction step and the system's energy were simulated. It is found that the first step reaction of the first hydrogen ion with the oxygen molecule is the controlling step of the overall reaction. Increasing the operating temperature speeds up the first step reaction rate and slightly decreases its reaction energy barrier. Our results provide insight into the working principles of HT-PEM fuel cells.

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Electrocatalysts for O2 reduction

Cited by 1,201 publications

References 36 publications

New applications and performance of bioelectrochemical systems

New applications and performance of bioelectrochemical systems

Reaproveitamento de óxidos de manganês de pilhas descartadas para eletrocatálise da reação de redução de oxigênio em meio básico

Oxygen reduction on a Pt(111) catalyst in HT-PEM fuel cells by density functional theory

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