The influence of ethene impurities in the gas feed of a PEM fuel cell

Kortsdottir, Katrin; Lindström, Rakel Wreland; Lindbergh, Göran

doi:10.1016/j.ijhydene.2012.06.119

Cited by 11 publications

(15 citation statements)

References 36 publications

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“…This can be seen in Figure 2 (top). Ethene ad-species are also partly reductively desorbable [3], but the amount is significantly smaller than in the case of propene. Even toluene ad-species are reductively desorbable to a small extent [4].…”

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confidence: 81%

“…Previous studies by our group indicate that although the effect of ethene in a fuel cell is small [3], toluene is a potential fuel cell poison [4]. Studies in acidic electrolyte [5] indicate that chain length has a considerable effect on the adsorption and oxidation of hydrocarbons on Pt catalyst.…”

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confidence: 94%

“…This can be seen in Figure 1, which depicts the stripping curves after exposure at various potentials. Similar to ethene [3], propene appears to be adsorbed mainly at catalytic sites that are not occupied by hydrogen. This can be concluded from the limited adsorption at potentials within the hydrogen region and the subsequent increase in the oxidation peak size as the adsorption potential increases towards the upper limit of the region, after which is starts to decrease again as the adsorption potential increases into the oxidation range.…”

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confidence: 96%

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Reformate Hydrogen Fuel in PEM Fuel Cells: the Effect of Alkene Impurities on Anode Activity

Kortsdottir¹,

Ferriz²,

Lagergren³

et al. 2013

ECS Trans.

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Reformate hydrogen contains many impurities, some are well known while others have been less studied. Hydrocarbons are possible impurities in reformate hydrogen and are among those less studied. This study if aimed at alkenes, with special focus on propene. Adsorption and desorption on the Pt catalyst is studied using stripping cyclic voltammetry combined with mass spectrometry. The results show that although the effect of propene in the presence of hydrogen is expected to be minimal, adsorption and blockage of catalytic sites cannot be ruled out. A small amount of ad-species is formed on Pt at low adsorption potentials, and in the presence of hydrogen, although suppression of the hydrogen desorption peak was minimal if hydrogen was adsorbed on the Pt catalyst prior to exposure.

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confidence: 81%

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confidence: 94%

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confidence: 96%

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Reformate Hydrogen Fuel in PEM Fuel Cells: the Effect of Alkene Impurities on Anode Activity

Kortsdottir¹,

Ferriz²,

Lagergren³

et al. 2013

ECS Trans.

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“…13,14 The experimental setup was identical to that used in a previous study, 14 with a cell housing from ElectroChem, Inc connected to a PAR potentiostat. The MEA was activated according to the previously described procedure, 13,14 except for the adjustment of the higher potential limit in the case of PtRu from 1.2 to 0.9 V, to avoid Ru oxidation and subsequent dissolution and loss of catalyst.…”

Section: Methodsmentioning

confidence: 99%

Influence of Hydrogen and Operation Conditions on CO2 Adsorption on Pt and PtRu Catalyst in a PEMFC

Kortsdottir¹,

Domínguez²,

Lindström³

2013

ECS Electrochemistry Letters

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CO 2 is a major component in reformate gas and can, as a source of CO, be a catalyst poison in polymer electrolyte membrane fuel cells. The effect of CO 2 on cell performance is not fully understood in the presence of hydrogen. This paper addresses the influence of hydrogen on CO 2 adsorption on Pt/C and PtRu/C catalysts. The results show that the reduction and adsorption of CO 2 is slow but increases if hydrogen is present, especially on PtRu/C. Further, exposure to a CO 2 and H 2 mixture at 0.15 V on PtRu/C results in current oscillations, which are dependent on operation conditions. Reformate gas inevitably contains 10-30% CO 2 and traces of CO, even after several purification steps. While numerous studies exist on the influence of CO on fuel cell performance, see reviews 1-3 and references therein, the effect of CO 2 is less studied. Although CO 2 is potentially harmless in a fuel cell, studies have shown 4,5 that 20-25% CO 2 in the hydrogen fuel induces performance losses that cannot be explained by dilution only. It is generally argued that CO 2 is transformed to CO in the fuel cell, due to the reverse water-gas shift (RWGS) reaction 4or by an electrochemical reduction mechanism, 6 such asalthough the latter has been questioned due to its low standard potential of −0.2 V. 7 According to thermodynamic calculations the RWGS reaction would give rise to CO concentrations of about 15-100 ppm in equilibrium with a 20-25% CO 2 /H 2 gas mixture 2,8,9 depending on temperature and humidity. However, the moderate effects of CO 2 in operating fuel cells 8,10 indicates that much lower concentrations must be present, presumably due to slow kinetics of both the RWGS reaction 9,11 and the electroreduction of CO 2 8 at PEM fuel cell conditions. Using PtRu as a catalyst instead of Pt has been shown to improve the tolerance of CO 2 in the hydrogen gas, 4,5,9,12 but there is some controversy as to whether it is only due to the improved tolerance to CO,11,12 or if Ru somehow hinders the transformation of CO 2 to CO. 4,9 This study sheds further light on the interplay between hydrogen and CO 2 in a fuel cell both on Pt/C and PtRu/C catalyst and how this is affected by operation conditions, in particular the influence of relative humidity and the presence or absence of H 2 . ExperimentalMembrane electrode assemblies (MEA) were prepared using Tanaka catalysts (TEC10E40E, 36% Pt, and TEC61E54, 29.7% Pt and 23.0% Ru (1:1.5) both on high surface carbon) and N115 membranes, as previously described. 13,14 The experimental setup was identical to that used in a previous study, 14 with a cell housing from ElectroChem, Inc connected to a PAR potentiostat. The MEA was activated according to the previously described procedure, 13,14 except for the adjustment of the higher potential limit in the case of PtRu from 1.2 to 0.9 V, to avoid Ru oxidation and subsequent dissolution and loss of catalyst.As a standard experiment, CO 2 was allowed to enter the cell at a potential hold at 0.15 V for 30 min followed by a 5 min purge with N 2 . These time...

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“…Nesta diferentes grupos amônio-quaternários e relacioná-los ao desempenho de AEMFCs. 95 Resultados e Discussão ___________________________________________________________________…”

Section: Efeito Da Combinação De Aeis E Aems Funcionalizados Por Difeunclassified

Influência dos contaminadores do hidrogênio produzido pela desidrogenação do etanol no desempenho de células a combustível de membranas protônicas e aniônicas

Biancolli¹

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Influência dos contaminadores do hidrogênio produzido pela desidrogenação do etanol no desempenho de células a combustível de membranas protônicas e aniônicasTese apresentada ao Instituto de Química de São Carlos da Universidade de São Paulo como parte dos requisitos para a obtenção do título de doutor em ciências. Área de concentração: Físico-Química Orientador: Prof. Dr. Edson A. Ticianelli SÃO CARLOS 2019 Dedico esta tese de doutorado aos meus pais, Oraíde e Leacir, por sempre acreditarem em minha capacidade, pela educação que me deram, carinho, amor e oportunidades que me guiaram até aqui. Obrigada por sempre estarem ao meu lado. "O sucesso é ir de fracasso em fracasso sem perder o entusiasmo". Winston Churchill RESUMO Neste trabalho, foi estudada a influência dos principais contaminadores presentes no hidrogênio produzido pela desidrogenação catalítica do etanol (acetato de etila, acetaldeído e etanol não reagido) no desempenho de células a combustível de membranas protônicas (PEMFCs) e aniônicas (AEMFCs). As investigações compreenderam a elucidação dos processos e reações envolvidos nos correspondentes sistemas eletródicos, bem como dos fenômenos que governam o desempenho eletroquímico nos meios alcalino e ácido, na ausência e na presença dos subprodutos oriundos da desidrogenação. Para as AEMFCs, as pesquisas inicialmente compreenderam a síntese de ionômeros e membranas e a otimização de seus desempenhos em células unitárias, utilizando hidrogênio puro e catalisadores eletródicos convencionais (Pt-Ru/C no ânodo e Pt/C no cátodo). Através da análise por diferentes técnicas, foi possível esclarecer que o etanol não reagido é o principal veneno no caso das PEMFCs, sendo que o acetaldeído e o acetato de etila têm contribuições menores para este envenenamento. Foram investigados diferentes eletrocatalisadores nos eletrodos a fim de se obter melhores desempenhos, sendo que o melhor resultado foi observado quando se utilizou o catalisador de Pt-Co/C no cátodo da célula (e Pt/C no ânodo), sendo que em 0,7 V a perda em densidade de potência foi de apenas 20% em comparação à uma célula alimentada por H2 puro e com Pt/C em ambos os eletrodos. No caso da AEMFC, foi possível obter ionômeros inéditos, que combinados com as membranas sintetizadas, resultaram em células com densidade de potência máxima acima de 1 W cm -2 . No entanto, devido à instabilidade química, ao serem expostos aos contaminadores, os materiais parecem sofrer degradação, o que leva à perda quase total e irreversível do desempenho da célula.ABSTRACT In this work, the influence of the main contaminants present in the hydrogen produced by the catalytic dehydrogenation of ethanol (ethyl acetate, acetaldehyde and unreacted ethanol) on the performance of proton exchange membrane fuel cells (PEMFCs) and anion exchange membrane fuel cells (AEMFCs) were studied. Investigations comprised the elucidation of the processes and reactions involved in the corresponding electrode systems, as well as the phenomena governing the electrochemical performance in the alkal...

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The influence of ethene impurities in the gas feed of a PEM fuel cell

Cited by 11 publications

References 36 publications

Reformate Hydrogen Fuel in PEM Fuel Cells: the Effect of Alkene Impurities on Anode Activity

Reformate Hydrogen Fuel in PEM Fuel Cells: the Effect of Alkene Impurities on Anode Activity

Influence of Hydrogen and Operation Conditions on CO2 Adsorption on Pt and PtRu Catalyst in a PEMFC

Influência dos contaminadores do hidrogênio produzido pela desidrogenação do etanol no desempenho de células a combustível de membranas protônicas e aniônicas

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