Electrooxidation of Carbon Monoxide at Ruthenium–Modified Platinum Nano‐particles: Evidence for CO Surface Mobility

Maillard, Frédéric; Gloaguen, Frédéric; Hahn, F.; Léger, Jean‐Michel

doi:10.1002/fuce.200290013

Cited by 46 publications

(70 citation statements)

References 45 publications

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“…As reported in previous publications, the peak splitting has been usually found on Ru-modified Pt or Pt single crystal electrodes [4,23,24]. On PtRu electrodes, the two peak voltammetric behaviour was considered to reflect the existence of two kinds of CO species: CO species adsorbed at either Ru sites or at Pt sites neighbouring in Ru sites and CO species adsorbed at Pt sites far away from Ru sites.…”

Section: Resultsmentioning

confidence: 99%

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The effect of CeO₂ on Pt/CeO₂/CNT catalyst for CO electrooxidation

Yuan

Guo

et al. 2009

Fuel Cells

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Pt/CeO2/CNT catalysts were prepared by adsorbing Pt nanoparticles on the supports of CNTs coated with CeO2. The electrocatalytic performances in respect to the electrooxidation of chemisorbed CO were tested using potential step and stripping voltammetry methods under variable sweep rate and temperature conditions. At 10 mV s–1, the CO stripping voltammogram exhibited the peak splitting phenomenon. The oxidation charge and the peak potential of the two voltammetric peaks changed regularly with the number of Pt and CeO2 neighbours, the sweep rate, and the temperature. We considered that the low potential peak originated from the reaction of COads with hydroxyl groups on CeO2 adjacent to Pt sites, while the high potential peak came from the reaction of COads with hydroxyl groups produced on pure Pt. Furthermore, the experimental results of the peak potential against the logarithm of the sweep rate and the logarithm of the current maximum time against the step potential were plotted and intersecting lines with different slopes in high and low potential regions in the plot were observed. The lines intersected at lower potentials on the Pt/CeO2/CNT electrode than on the Pt/CNT electrode, which was attributed to the contribution of hydroxyl groups on CeO2.

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Section: Resultsmentioning

confidence: 99%

“…The bifunctional mechanism has been widely accepted for explaining the process of CO electrooxidation [3,4]. Based on this mechanism, a second metal element, such as Ru, which can dissociate H 2 O under lower potentials than Pt, has been used to promote the CO electrooxidation.…”

Section: Introductionmentioning

confidence: 99%

The effect of CeO₂ on Pt/CeO₂/CNT catalyst for CO electrooxidation

Yuan

Guo

et al. 2009

Fuel Cells

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“…This characteristic induces a hard conversion of ethanol into carbon dioxide due to the difficult to break the C-C bond and promote the complete oxidation of the methyl group with Pt as electrocatalyst. [7][8][9] Several studies on the ethanol electrooxidation focused mainly to identify adsorbed intermediates showed the presence of carbon monoxide species strongly adsorbed at the electrode surface. Many studies using Differential Electrochemical Mass Spectrometry (DEMS) and in situ Fourier Transform Infrared Reflectance Spectroscopy (FTIRS) provided identification of intermediates Ethanol Electrooxidation on Pt-Sn and Pt-Sn-W Bulk Alloys J. Braz.…”

Section: Introductionmentioning

confidence: 99%

Ethanol electrooxidation on Pt-Sn and Pt-Sn-W bulk alloys

Anjos¹,

Hahn²,

Léger³

et al. 2008

J. Braz. Chem. Soc.

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A oxidação de etanol foi estudada sobre eletrodos Pt-Sn e Pt-Sn-W preparados em forno a arco elétrico. Diferentes técnicas eletroquímicas, tais como voltametria cíclica e cronoamperometria foram utilizadas para avaliar a atividade catalítica desses materiais. O processo de eletro-oxidação também foi investigado in situ por espectroscopia de reflectância na região do infravermelho para determinar intermediários adsorvidos e produtos da reação. Os resultados experimentais indicaram que as ligas Pt-Sn e Pt-Sn-W são capaz de oxidar etanol principalmente para acetaldeído e ácido acético. CO adsorvido também foi detectado, demonstrando a viabilidade do rompimento da ligação C-C na molécula de etanol durante o processo de oxidação. Adicionalmente, o CO adsorvido foi oxidado a CO 2 . Esse produto de reação foi claramente detectado por SNIFTIRS. O catalisador Pt-Sn-W mostrou um melhor desempenho eletroquímico em relação ao Pt-Sn e este, por sua vez, é melhor do que Pt pura.Ethanol oxidation has been studied on Pt-Sn and Pt-Sn-W electrodes prepared in an arc-melting furnace. Different electrochemical techniques like cyclic voltammetry and chronoamperometry were used to evaluate the catalytic activity of these materials. The electro-oxidation process was also investigated by in situ infrared reflectance spectroscopy in order to determine adsorbed intermediates and reaction products. Experimental results indicated that Pt-Sn and Pt-Sn-W alloys are able to oxidize ethanol mainly to acetaldehyde and acetic acid. Adsorbed CO was also detected, demonstrating the viability of splitting the C-C bond in the ethanol molecule during the oxidation process. The adsorbed CO was further oxidized to CO 2 .This reaction product was clearly detected by SNIFTIRS. Pt-Sn-W catalyst showed a better electrochemical performance than Pt-Sn that, in it turn, is better than Pt-alone.Keywords: ethanol oxidation, direct ethanol fuel cell, platinum-tin, platinum-tin-tungsten, in situ Infrared Reflectance Spectroscopy IntroductionEthanol is a molecule of considerable interest because of its importance and potential use as renewable fuel (can be obtained from sugar cane for example) for fuel cells applications.1-4 Among the various alcohols which can be used as alternative fuel, ethanol is the most promising one because it is a safer molecule comparatively to methanol. As a liquid, it is easy to store and handle when comparing to hydrogen. Moreover, ethanol has a high theoretical energy (8 kWh kg -1 against 6.1 kWh kg -1 for methanol and 33 kWh kg -1 for pure hydrogen without storage). 5,6 Ethanol main disadvantage comes from its molecular structure with a carbon containing a primary alcohol function and a methyl group. This characteristic induces a hard conversion of ethanol into carbon dioxide due to the difficult to break the C-C bond and promote the complete oxidation of the methyl group with Pt as electrocatalyst. [7][8][9] Several studies on the ethanol electrooxidation focused mainly to identify adsorbed intermediates showed the presence of carbo...

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“…[35][36][37] It is known that only one CO adsorption band is observed on the PtRu alloy surface, indicating that separated Pt and Ru phases should exist in the present PtRu/C catalyst, [38][39][40][41] which coincides with the low alloying degree of Ru in the PtRu/C catalyst, as listed in Table I. The CO L intensity increases slightly with potential, while its peak position shifts to a higher frequency region, which can be attributed to the electron back-donation from the Pt to CO antibonding orbit.…”

Section: B866mentioning

confidence: 95%

Effect of SnO[sub 2] Deposition Sequence in SnO[sub 2]-Modified PtRu/C Catalyst Preparation on Catalytic Activity for Methanol Electro-Oxidation

Wang

Takeguchi

Zhang

et al. 2009

J. Electrochem. Soc.

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SnO 2 -modified PtRu/C catalysts were prepared in a polyol process to investigate the effect of a SnO 2 deposition sequence on the catalytic activity for methanol electro-oxidation. The structure, morphology, and chemical state of the prepared catalysts were characterized by X-ray diffraction, scanning transmission electron microscopy, and X-ray photoelectron spectroscopy. The electrochemical activities were evaluated by cyclic voltammetry, linear sweep voltammetry, and chronoamperometry measurements in combination with in situ IR reflection-absorption spectroscopy ͑IRRAS͒. Compared with those in the PtRu/C catalyst, a simultaneous deposition of PtRu and SnO 2 particles or a deposition of SnO 2 prior to PtRu improved the metal dispersion and decreased the alloyed Ru fraction. The deposition sequence of SnO 2 did not alter the chemical-state distribution of Pt and Ru but resulted in a different surface atomic ratio of Pt, Ru, and SnO 2 . Electrochemical and in situ IRRAS measurements indicated that the SnO 2 -modified PtRu/C catalyst prepared by the deposition of PtRu prior to SnO 2 gave the best catalytic activity for CO ads and methanol electro-oxidation among the PtRu/C and SnO 2 -modified PtRu/C catalysts. The roles of SnO 2 deposited with different sequences in the SnO 2 -modified PtRu/C catalysts were proposed. The electro-oxidation of methanol has attracted considerable interest due to its importance for direct methanol fuel cells ͑DMFCs͒, and the PtRu/C catalyst has been recognized as the most active binary catalyst. 1 The enhanced performance on the PtRu/C catalyst is usually explained by a bifunctional mechanism, 2-4 where methanol is adsorbed and dehydrogenated to produce CO ads on Pt active sites, Ru is more active than Pt to provide OH ads at low potentials by a water-discharge reaction, and CO ads on Pt active sites reacts with the neighboring OH ads to yield CO 2 . A PtRu alloy is also thought to weaken CO adsorption on Pt active sites by the electronic effect. [5][6][7]

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Electrooxidation of Carbon Monoxide at Ruthenium–Modified Platinum Nano‐particles: Evidence for CO Surface Mobility

Cited by 46 publications

References 45 publications

The effect of CeO₂ on Pt/CeO₂/CNT catalyst for CO electrooxidation

The effect of CeO₂ on Pt/CeO₂/CNT catalyst for CO electrooxidation

Ethanol electrooxidation on Pt-Sn and Pt-Sn-W bulk alloys

Effect of SnO[sub 2] Deposition Sequence in SnO[sub 2]-Modified PtRu/C Catalyst Preparation on Catalytic Activity for Methanol Electro-Oxidation

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Electrooxidation of Carbon Monoxide at Ruthenium–Modified Platinum Nano‐particles: Evidence for CO Surface Mobility

Cited by 46 publications

References 45 publications

The effect of CeO2 on Pt/CeO2/CNT catalyst for CO electrooxidation

The effect of CeO2 on Pt/CeO2/CNT catalyst for CO electrooxidation

Ethanol electrooxidation on Pt-Sn and Pt-Sn-W bulk alloys

Effect of SnO[sub 2] Deposition Sequence in SnO[sub 2]-Modified PtRu/C Catalyst Preparation on Catalytic Activity for Methanol Electro-Oxidation

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The effect of CeO₂ on Pt/CeO₂/CNT catalyst for CO electrooxidation

The effect of CeO₂ on Pt/CeO₂/CNT catalyst for CO electrooxidation