Adsorbed water for the electro-oxidation of methanol at Pt–Ru alloyElectronic supplementary information (ESI) available: additional explanation for Figs. 2 and 3. See http://www.rsc.org/suppdata/cc/b2/b212197b/

Yajima, Takahiro; Wakabayashi, Noriaki; Uchida, Hiroyuki; Watanabe, Masahiro

doi:10.1039/b212197b

Cited by 99 publications

(87 citation statements)

References 21 publications

(28 reference statements)

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“…[10][11][12] This model has been complemented by an electronic effect (ligand effect). 13,14 Accordingly, Ru produces perturbations in the energy of the surface d-band of Pt, 13,15 which can result in modifications on both the strength of Pt-(CO) bond and the activation energy of reaction, in such a way that on Pt surfaces modified by Ru, Pt-(CO) might be easily oxidized to CO2 at potentials lower than those required in Pt alone.…”

Section: Introductionmentioning

confidence: 99%

“…19 The combined action of bifunctional mechanism and electronic effect has been proposed to explain the role of Pt-Ru during CO electro-oxidation, 13 but the bifunctional mechanism is still the predominant model to explain the behavior of such systems. 1,11,12,[20][21][22] The bifunctional mechanism requires that during CO electro-oxidation the limiting step reaction at low overpotentials is a bimolecular collision between neighboring Pt κ -(CO) and an activated Ru γ -(H2O) species at a threshold potential via a LangmuirHinshelwood mechanism, being the formation of the last species promoted on Ru domains. For CO oxidation on a Pt-Ru electrode, it means that Ru domains must act as centers for nucleation of oxygen-containing species, and the occurrence of the bifunctional mechanism requires COads diffusion from Pt domains to active Pt sites near Ru sites.…”

Section: Introductionmentioning

confidence: 99%

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Disentangling Catalytic Activity at Terrace and Step Sites on Selectively Ru-Modified Well-Ordered Pt Surfaces Probed by CO Electro-oxidation

et al. 2016

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In heterogeneous (electro)catalysis, the overall catalytic output results from responses of surface sites with different catalytic activities, and their discrimination in terms of what specific site is responsible for a given activity is not an easy task. Here, we use the electrooxidation of CO as a probe reaction to access the catalytic activity of different sites on high Miller index stepped Pt surfaces with their {110} steps selectively modified by Ru at different coverage. Data from in situ FTIR spectroscopy and cyclic voltammetry evidence that Ru deposited on {110} steps modifies the surface in a non-trivial way, only favoring the electrocatalytic oxidation of CO over {111} terraces. Moreover, these {111} terraces become catalytically active throughout a large potential window. On the other hand, after the deposition of Ru on {110} steps, the partial oxidation of a CO adlayer (by stripping voltammetry and in situ FTIR potential steps) show that those {110} steps that remain free of Ru seem to be not influenced by the presence of this metal. As a result, the remaining CO adlayer is oxidized on these Ru-free {110} steps at potentials identical to those observed in steps of pure stepped Pt surfaces (in absence of Ru). Firstly, these This is a previous version of the article published in ACS Catalysis. 2016, 6(5): 2997-3007. doi:10.1021/acscatal.6b00439 2 findings suggest that COads behaves as a motionless species during its oxidation. Secondly, they evidence that the impact caused by the presence of Ru in the catalytic activity of Pt(s)-[(n-1)(111)×(110)] stepped surfaces depends on the crystallographic orientation of Pt sites. These results help us to shed new light about the role of Ru in the mechanism of oxidation of CO and allow a deeper understanding regarding the CO tolerance in Pt-Ru catalysts.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Disentangling Catalytic Activity at Terrace and Step Sites on Selectively Ru-Modified Well-Ordered Pt Surfaces Probed by CO Electro-oxidation

et al. 2016

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“…We have investigated the methanol oxidation reaction (MOR) and the CO ad oxidation at various catalysts. [119][120][121][122][123] The E onset for the MOR was found to coincide well with that for the CO ad oxidation reaction (CO ad OR) at Pt and Pt-Ru alloys, 121,122 because CO ad is the intermediate in the MOR, with a facile dehydrogenation reaction. Among various catalysts examined in acidic media, Pt-Ru alloys have exhibited the highest activity for the MOR or CO ad OR from 20 to 120°C.…”

Section: Anode Catalysts For Direct Oxidation Fuel Cellsmentioning

confidence: 78%

“…120,123 By in situ ATR-FTIR for CO-adsorbed Pt/CB, Pt 3 Co/CB, and PtRu/CB from 23 to 60°C, a sharp band around 3630 cm ¹1 was observed, which was assigned to¯(OH) of non-hydrogen bonded, isolated water (co-adsorbed with CO). 13,18,121 Changes in the¯(OH) during the CO ad OR clearly indicated that the dominant factor for determining the oxidation activity was the E onset for the oxidation of the isolated water to provide an oxygen species (Pt-OH or Ru-OH). The values of E onset (H 2 O) at PtRu/CB were lowest among the three catalysts.…”

Section: Anode Catalysts For Direct Oxidation Fuel Cellsmentioning

confidence: 99%

Research and Development of Highly Active and Durable Electrocatalysts Based on Multilateral Analyses of Fuel Cell Reactions

Uchida

2017

Electrochemistry

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In order to establish clear strategies for the design of electrocatalysts with high activity and high durability, fuel cell reactions have been analyzed by multilateral techniques. The use of monodisperse Pt or Pt-alloy nanocatalysts with uniform composition, which were highly dispersed over the whole surface of the carbon support by the nanocapsule method, contributed greatly in clarifying the effects of various properties (particle size, composition, and surface structure, etc.) towards the activity and durability for the anode and cathode in polymer electrolyte fuel cells (PEFCs). New catalyst layers have been developed in order to make the electrocatalysts work effectively specifically under low humidity. Several important concepts have been demonstrated for developing high-performance oxygen and hydrogen electrodes with high durability for a reversible solid oxide cell (R-SOC), which is expected to be a reciprocal direct energy converter between hydrogen and electricity with high efficiency.

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“…One is the bifunctional mechanism proposed by Watanabe and his colleagues. [28][29][30][31] It is based on the promotion of CO oxidation on Pt atoms by a second metal which provides OH-type species at lower potential. The more oxidizable second metal, thus, promotes CO electrooxidation.…”

Section: Introductionmentioning

confidence: 99%

Study of CO Oxidation on Well-Characterized Pt-Ru/C Electrocatalysts Having Different Composition

Min¹,

Kim²,

Kim³

2010

Bulletin of the Korean Chemical Society

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In this paper, we characterized bimetallic Pt-Ru/C alloy catalysts having four different compositions and compared the catalytic activities of the prepared alloys for CO oxidation. ICP-AES, EDS, XRD, TEM, and XAS were used to investigate the composition, degree of alloying, particle size, and electronic structure of the prepared Pt-Ru/C catalysts. Those results indicated the synthesis of the alloy catalysts with intended composition and uniform size. The electrochemical study of the characterized alloys showed higher catalytic activity for CO oxidation than that of the commercial Pt/C (E-TEK, Inc., 20 wt %) catalyst. Especially, it was shown that the alloy catalyst with Ru composition of 50 atomic % gave the highest catalytic activity for CO oxidation.

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Adsorbed water for the electro-oxidation of methanol at Pt–Ru alloyElectronic supplementary information (ESI) available: additional explanation for Figs. 2 and 3. See http://www.rsc.org/suppdata/cc/b2/b212197b/

Abstract: Adsorbed water molecules which promote the methanol oxidation reaction (MOR) at Pt-Ru alloy electrode are clearly detected by in-situ FTIR spectroscopy with the attenuated total reflection configuration, which directly supports the "bi-functional mechanism" for the MOR.

Cited by 99 publications

References 21 publications

Disentangling Catalytic Activity at Terrace and Step Sites on Selectively Ru-Modified Well-Ordered Pt Surfaces Probed by CO Electro-oxidation

Disentangling Catalytic Activity at Terrace and Step Sites on Selectively Ru-Modified Well-Ordered Pt Surfaces Probed by CO Electro-oxidation

Research and Development of Highly Active and Durable Electrocatalysts Based on Multilateral Analyses of Fuel Cell Reactions

Study of CO Oxidation on Well-Characterized Pt-Ru/C Electrocatalysts Having Different Composition

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