CO Tolerance of Pt alloy electrocatalysts for polymer electrolyte fuel cells and the detoxification mechanism

Igarashi, Hiroshi; Fujino, Takeshi; Zhu, Yimin; Uchida, Hiroyuki; Watanabe, Masahiro

doi:10.1039/b007768m

Cited by 352 publications

(317 citation statements)

References 31 publications

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“…10,1316) For example, Stamenkovic et al evaluated the ORR activities for the (111), (100) and (110) single crystal planes of a Pt 3 Ni intermetallic compound; their pioneering work clearly demonstrates that the (111) surface has a superior ORR activity. 13) Furthermore, molecular beam epitaxy (MBE) and ultra-high-vacuum (UHV) techniques enable the creation of well-defined bimetallic surfaces, and we have that the activities of the MBE-prepared Ni 0.3nm / Pt(111), 15) Co 0.3nm /Pt(111), (100), (110) 14,17) and Pt 0.3nm / Au(111) 18) bimetallic surfaces are very sensitive to the topmost and sub-surface structures.…”

Section: Introductionmentioning

confidence: 99%

Platinum-Enriched Ni/Pt(111) Surfaces Prepared by Molecular Beam Epitaxy: Oxygen Reduction Reaction Activity and Stability

et al. 2013

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Oxygen reduction reaction (ORR) activities and electrochemical stabilities were evaluated for Ni/Pt(111) model electrode-catalysts fabricated by molecular beam epitaxy (MBE). Exposure of clean Pt(111) to 1.0-Langmuir (i.e., fractional coverage, ª = 1.0 in the Langmuir isotherm) CO at 300 K produced linear-bonded and bridge-bonded COPt IR bands at 2093 and 1858 cm ¹1. In contrast, 3.0-nm-thick Ni deposition onto Pt(111) at 823 K (823 K-Ni 3.0nm /Pt(111)) showed broad IR bands for adsorbed CO at around 2064 cm ¹1 ; the separation of reflection high-energy electron diffraction (RHEED) streaks of the 823 K-Ni 3.0nm /Pt(111) is greater than for clean Pt(111). In contrast, 923 KNi 3.0nm /Pt(111) yielded a single sharp IR band because of linear-bonded CO at 2080 cm ¹1, and the separation of the RHEED streaks is almost the same as that for the Pt(111). The results suggest that a Pt-enriched topmost surface is generated above 923 K through surface segregation of the substrate Pt atoms during the Ni deposition. After transferring the sample from ultra-high vacuum to an electrochemical system, without being exposed to air, changes in ORR activities of the MBE-prepared 923 K-Ni 3.0nm /Pt(111) were evaluated in a 0.1-mol L ¹1 HClO 4 aqueous solution under applied potential cycles of between 0.6 and 1.0 V vs. RHE. The ORR activity enhancement factor vs. clean Pt(111) for the asprepared 923 K-Ni 3.0nm /Pt(111) was estimated to be twelve, and this factor was reduced to four after the application of 1000 potential cycles. However, a 943 K-Ni 3.0nm /Pt(111) sample, which showed a relatively low ORR activity (an enhancement factor of eight), had the activity enhancement factor of six even after the application of 1000 potential cycles. These results reveal that the sub-surface structures and composition of Pt-based alloys determine not only initial ORR activity but also electrochemical durability of the ORR catalysts.

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Section: Introductionmentioning

confidence: 99%

Platinum-Enriched Ni/Pt(111) Surfaces Prepared by Molecular Beam Epitaxy: Oxygen Reduction Reaction Activity and Stability

et al. 2013

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“…This should be due to an increased 5d vacancy of Pt by Ru on the Pt-Ru electrode, which is considered to decrease the back donation from Pt 5d orbital to CO 2π* orbital, contributing to the chemisorption of CO onto the Pt surface. 24,25 Amperometric detection of CO with various concentrations in saline is shown in Fig. 4a.…”

Section: Preparation and Co Detection Properties Of Pt-ru Electrodementioning

confidence: 99%

Sensitive and Selective Electrochemical Detection of Carbon Monoxide in Saline at a Pt-Ru/Nafion/MnO2-Modified Electrode

2012

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Section: Introductionmentioning

confidence: 99%

“…[8][9][10][11] This outstanding characteristic is explained by two different effects, namely the bifunctional 12,13 and electronic or binder effects. [14][15][16] The bifunctional effect, first described by Watanabe and Motoo, 12,13 ocurrs when elements less noble than Pt and with high affinity for water molecules, such as Ru, easily form oxygen or hydrated oxides species next to a Pt site onto which the organic intermediate is adsorbed. The electronic effect or binder is identified when one metal present in the alloy can change the chemical properties of the first layer of Pt atoms on the catalysts surface, thereby lowering the electronic density at the Fermi level.…”

Section: Introductionmentioning

confidence: 99%

“…As a consequence, the number of free Pt sites for adsorption and oxidation of molecules is increased. [14][15][16] Neto et al 17 have described that introduction of Ru into Pt-based catalysts enhances the reactivity towards oxidation and moderates the poisoning effect through formation of meta-stable intermediates, via the bifunctional mechanism.Sn catalysts can electronically modify the electron in the d bands of Pt by changing the adsorption energy. In addition, materials that have Ni in the presence of Ru and/or Sn have furnished promising results regarding the ethanol oxidation in DEFC.…”

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Development of plurimetallic electrocatalysts prepared by decomposition of polymeric precursors for EtOH/O2 fuel cell

Palma¹,

Almeida²,

Andrade³

2012

J. Braz. Chem. Soc.

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Este trabalho teve como objetivo desenvolver eletrocatalisadores plurimetálicos contendo Pt, Ru, Ni e Sn suportados em C pelo método de decomposição de precursores poliméricos (DPP), na razão metal:carbono de 40:60% em massa, para aplicação em célula a combustível de etanol direta (DEFC). As nanopartículas obtidas foram caracterizadas físico-quimicamente por difração de raios X (DRX) e energia dispersiva de raios X. Os resultados de DRX revelaram cristalitos com estrutura cúbica de face centrada da Pt com evidências de que os átomos de Ni, Ru e Sn foram incorporados à estrutura da Pt. A caracterização eletroquímica das nanopartículas foi realizada por voltametria cíclica e cronoamperometria em meio ácido (H 2 SO 4 0,05 mol L -1 ), na ausência e presença de etanol. A adição de Sn para os catalisadores PtRuNi/C deslocou significativamente o potencial de início de oxidação de etanol e CO para valores mais baixos, aumentando assim a atividade catalítica, especialmente para a composição Pt 64 Sn 15 Ru 13 Ni 8 /C. Eletrólises de solução de etanol em 0,4 V vs. ERH permitiram a determinação de acetaldeído e ácido acético como principais produtos da reação. A presença de Ru nas ligas favoreceu a formação de ácido acético como produto principal da oxidação do etanol. O catalisador Pt 64 Sn 15 Ru 13 Ni 8 /C exibiu o melhor desempenho para DEFC.This work aimed to develop plurimetallic electrocatalysts composed of Pt, Ru, Ni, and Sn supported on C by decomposition of polymeric precursors (DPP), at a constant metal:carbon ratio of 40:60 wt.%, for application in direct ethanol fuel cell (DEFC). The obtained nanoparticles were physico-chemically characterized by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). XRD results revealed a face-centered cubic crystalline Pt with evidence that Ni, Ru, and Sn atoms were incorporated into the Pt structure. Electrochemical characterization of the nanoparticles was accomplished by cyclic voltammetry (CV) and chronoamperometry (CA) in slightly acidic medium (0.05 mol L -1 H 2 SO 4 ), in the absence and presence of ethanol. Addition of Sn to PtRuNi/C catalysts significantly shifted the ethanol and CO onset potentials toward lower values, thus increasing the catalytic activity, especially for the quaternary composition Pt 64 Sn 15 Ru 13 Ni 8 /C. Electrolysis of ethanol solutions at 0.4 V vs. RHE allowed determination of acetaldehyde and acetic acid as the main reaction products. The presence of Ru in alloys promoted formation of acetic acid as the main product of ethanol oxidation. The Pt 64 Sn 15 Ru 13 Ni 8 /C catalyst displayed the best performance for DEFC. Keywords: DEFC, ethanol, decomposition of polymeric precursor method (DPP), metallic catalyst IntroductionThe development of clean technologies for power generation with renewable fuels is required if we are to overcome the increase in environmental problems. In this context, the use of ethanol as fuel is promising because it is renewable, easy to store and handle, and contains high energy density (8 kW h kg -1 ),...

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CO Tolerance of Pt alloy electrocatalysts for polymer electrolyte fuel cells and the detoxification mechanism

Cited by 352 publications

References 31 publications

Platinum-Enriched Ni/Pt(111) Surfaces Prepared by Molecular Beam Epitaxy: Oxygen Reduction Reaction Activity and Stability

Platinum-Enriched Ni/Pt(111) Surfaces Prepared by Molecular Beam Epitaxy: Oxygen Reduction Reaction Activity and Stability

Sensitive and Selective Electrochemical Detection of Carbon Monoxide in Saline at a Pt-Ru/Nafion/MnO2-Modified Electrode

Development of plurimetallic electrocatalysts prepared by decomposition of polymeric precursors for EtOH/O2 fuel cell

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