Mechanistic study of the reduction of oxygen in air electrode with manganese oxides as electrocatalysts

Mao, Lanqun; Zhang, Dun; Sotomura, Tadashi; Nakatsu, Kenichi; Koshiba, Nobuharu; Ohsaka, Takeo

doi:10.1016/s0013-4686(02)00815-0

Cited by 347 publications

(192 citation statements)

References 26 publications

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“…O número de elétrons envolvidos na RRO pode ser estimado a partir do coeficiente angular deste gráfico, 25 de acordo com a Equação 5.…”

Section: Caracterização Eletroquímicaunclassified

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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“…O número de elétrons envolvidos na RRO pode ser estimado a partir do coeficiente angular deste gráfico, 25 de acordo com a Equação 5.…”

Section: Caracterização Eletroquímicaunclassified

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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“…Among the non-precious metal alternatives, manganese oxides have received tremendous attentions owing to their low cost and nontoxicity, high elemental abundance, and appreciable ORR catalytic activity, when combined with a conductive support such as one dimensional (1D) carbon nanotubes, 2D graphene or 3D carbon frameworks [23][24][25][26]. As well known the decomposition of hydrogen peroxide formed during the electrochemical reduction of oxygen could be accelerated by manganese oxides [27,28]. However, manganese oxides decompose at low potential when they are directly exposed to harsh alkaline condition [29].…”

Section: Introductionmentioning

confidence: 99%

Encapsulated MnO in N-doping carbon nanofibers as efficient ORR electrocatalysts

et al. 2017

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Development of cheap, abundant and noblemetal-free materials as high efficient oxygen reduction electrocatalysts is crucial for future energy storage system. Here, one-dimensional (1D) MnO N-doped carbon nanofibers (MnO-NCNFs) were successfully developed by electrospinning combined with high temperature pyrolysis. The MnO-NCNFs exhibit promising electrochemical performance, methanol tolerance, and durability in alkaline medium. The outstanding electrocatalytic activity is mainly attributed to several issues. First of all, the uniform 1D fiber structure and the conductive network could facilitate the electron transport. Besides, the introduction of Mn into the precursor can catalyze the transformation of amorphous carbon to graphite carbon, while the improved graphitization means better conductivity, beneficial for the enhancement of catalytic activity for oxygen reduction reaction (ORR). Furthermore, the porous structure and high surface area can effectively decrease the mass transport resistance and increase the exposed ORR active sites, thus improve utilization efficiency and raise the quantity of exposed ORR active sites. The synergistic effect of MnO and NCNFs matrix, which enhances charge transfer, adsorbent transport, and delivers efficiency in the electrolyte solution, ensures the high ORR performance of MnO-NCNFs.

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“…Moreover, polypyrrole offers the advantage of an easy chemical [48] or electrochemical [49] synthesis. We selected Mn-based materials because of their well-known properties as an ORR electrocatalyst for alkaline systems [50][51][52]: high catalytic activity with the capability to decomposing hydrogen peroxide, environmental compatibility and low cost. Our choice of ternary systems intends to address two mechanisms of electrocatalytic enhancement: (i) stabilization of the Mn-based oxygen mediator species by doping with Co, Mg, and Ni; (ii) achievement of dual-function behavior by dispersing metallic nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Coelectrodeposition of Ternary Mn-Oxide/Polypyrrole Composites for ORR Electrocatalysts: A Study Based on Micro-X-ray Absorption Spectroscopy and X-ray Fluorescence Mapping

2015

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Low energy X-ray fluorescence (XRF) and soft X-ray absorption (XAS) microspectroscopies at high space-resolution are employed for the investigation of the coelectrodeposition of composites consisting of a polypyrrole(PPy)-matrix and Mn-based ternary dispersoids, that have been proposed as promising electrocatalysts for oxygen-reduction electrodes. Specifically, we studied Mn-Co-Cu/PP, Mn-Co-Mg/PPy and Mn-Ni-Mg/PPy co-electrodeposits. The Mn-Co-Cu system features the best ORR electrocatalytic activity in terms of electron transfer number, onset potential, half-wave potential and current density. XRF maps and micro-XAS spectra yield compositional and chemical state distributions, contributing unique molecular-level information on the pulse-plating processes. Mn, Ni, Co and Mg exhibit a bimodal distribution consisting of mesoscopic aggregates of micrometric globuli, separated by polymer-rich ridges. Within this common qualitative scenario, the individual systems exhibit quantitatively different chemical distribution patterns, resulting from specific electrokinetic and electrosorption properties of the single components. The electrodeposits consist of Mn in the as-fabricated material is a specific feature of the ternary systems, deriving from synergistic stabilisation brought about by two types of bivalent dopants as well as by galvanic contact to elemental metal; this result represents a considerable improvement in material quality with respect to previously studied Mn/PPy and Mn-based/PPy binaries.

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Mechanistic study of the reduction of oxygen in air electrode with manganese oxides as electrocatalysts

Cited by 347 publications

References 26 publications

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

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

Encapsulated MnO in N-doping carbon nanofibers as efficient ORR electrocatalysts

Coelectrodeposition of Ternary Mn-Oxide/Polypyrrole Composites for ORR Electrocatalysts: A Study Based on Micro-X-ray Absorption Spectroscopy and X-ray Fluorescence Mapping

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