Electrocatalytic oxidation of ethanol on Pt–Mo bimetallic electrodes in acid medium

Anjos, Daniela M.; Kokoh, K. Boniface; Léger, Jean‐Michel; Andrade, Adalgisa R. de; Olivi, Paulo; Tremiliosi‐Filho, Germano

doi:10.1007/s10800-006-9222-z

Cited by 64 publications

(74 citation statements)

References 36 publications

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“…The peak, which is observed at about 0.4 V (Fig. 4; A, curve b), is in agreement with earlier reports describing redox processes involving Mo(V) and Mo (VI) [40,[58][59][60][61]. Moreover, the presence of MoO 3 leads to an increase in the voltammetric peaks for hydrogen adsorption and desorption, which are presumably due to the hydrogen spillover effect within the hydrogen molybdenum bronze.…”

Section: Resultssupporting

confidence: 91%

Enhancement of activity of PtRh nanoparticles towards oxidation of ethanol through modification with molybdenum oxide or tungsten oxide

Miecznikowski

2012

J Solid State Electrochem

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Electrocatalytic systems utilizing carbon (Vulcan)-supported PtRh nanoparticles (PtRh/Vulcan) admixed with either molybdenum oxide or tungsten oxide were tested and compared during electrooxidation of ethanol. The systems' performance was diagnosed using electrochemical techniques such as voltammetry and chronoamperometry. The proposed electrocatalytic materials were also characterized with X-ray diffraction (XRD), transmission and scanning electron microscopies (TEM and SEM), as well as SEM-coupled energy dispersive X-ray spectroscopy (SEM-EDX). For both systems containing molybdenum and tungsten oxides, enhancements in catalytic activities (relative to the behavior observed at bare PtRh/Vulcan nanoparticles) were found during ethanol electrooxidation at room temperature (22°C). Further, it was from chronoamperometric current (density)-time responses that anodic electrocatalytic currents measured at 0.3 V (vs. RHE) were more than 20% higher in the case of the MoO 3 -containing PtRh/Vulcan system relative to that utilizing WO 3 . The diagnostic "CO-stripping" experiments were consistent with the view that addition of molybdenum oxide or tungsten oxide to PtRh/Vulcan tended to shift potential for the oxidation of inhibiting CO-adsorbate ca. 80 or 40 mV towards less negative values in comparison to the analogous but oxide-free system. The fact that carbon (Vulcan)-supported PtRu nanoparticles exhibited higher electrocatalytic reactivity observed phenomena may be attributed to specific interactions between noble metal centers and the oxides in addition to chemical reactivity of metal oxo groups in the vicinity of PtRh/ Vulcan at the electrocatalytic interface.

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Section: Resultssupporting

confidence: 91%

Enhancement of activity of PtRh nanoparticles towards oxidation of ethanol through modification with molybdenum oxide or tungsten oxide

Miecznikowski

2012

J Solid State Electrochem

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“…The electrical charges for hydrogen adsorption/desorption, Q H , that are transferred to Pt/C catalysts or materials modified with Mo, e.g., PtMo/C, make it possible to estimate the electroactive surface area (S ESA ). 24,25 The S ESA value is an indicator of the electrochemically active sites available per gram of catalyst, thereby being an important parameter for characterizing the electrochemical activity of Pt/C and Pt/Mo/C catalysts.…”

Section: Electrochemical Behavior Of Mo Modified Pt Electrodes-mentioning

confidence: 99%

Study of the Electrochemical Activities of Mo-Modified Pt Catalysts, for Application as Anodes in Direct Methanol Fuel Cells: Effect of the Aggregation Route

Reyes

Hernandez-Maya

Ocampo

et al. 2014

J. Electrochem. Soc.

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Electrocatalysts with constant metallic composition, consisting of carbon-supported platinum and molybdenum phases, were synthesized following the thermolysis (thr) and borohydride (bhr) reduction methods and using different metallic precursors. The obtained electrocatalysts were characterized by X-ray energy-dispersive spectrometry, X-ray diffraction and high resolution transmission electron microscopy. Their activities were studied by cyclic voltammetry. Different surface structures were obtained and the electrochemical activities toward methanol oxidation were compared. Pt, MoO 2 and MoO 3 phases were well identified with the characterization techniques used. However, the electrochemical responses obtained from both sample series were considerably different, suggesting that the arrangement and relationships between active phases strongly depend on the synthesis method and aggregation sequence of the metallic precursors, and being the cause of different catalytic activities and stabilities of molybdenum oxide phases. The bhr method offered higher activity than the thr method. Among the sample series obtained by bhr method, the catalyst obtained by platinum deposition on the previously synthesized molybdenum on carbon, led to the highest overall activity. Fuel Cells represent one of the most promising options for generating electricity with high efficiency and low environmental impact. The Direct-Methanol Fuel Cell (DMFC) is a low-temperature cell where methanol is directly supplied as fuel to the anode compartment, without any previous reforming. Furthermore, methanol can be stored and transported in liquid phase, it can be obtained from biomass, and its complete oxidation can yield a high energy density.1 Platinum has been recognized as the most active catalyst for the methanol oxidation reaction and it has been employed in the formulation of such materials. However, the formation of different organic intermediates, adsorbed on Pt surfaces during methanol electrooxidation, causes the poisoning of active sites and decreases the catalyst efficiency. Several studies indicate that the modification of the Pt catalyst with other transition metal can lead to good results in oxidizing methanol at a low potential (lower than in pure Pt). 2On the other hand, it is well known that bimetallic materials show increased activity toward the CO electro-oxidation reaction, yielding CO 2 . Studies on catalytic effects that take place on bimetallic surfaces, obtained from pure metals and modified by the deposition of a second metal, are closely related to the technological development of low temperature fuel cells. Some researchers have emphasized the use of CO as a test molecule to show the electronic effect associated with this reaction. The CO desorption energy is apparently related to strong intermetallic bonds and mixed orbitals of the active phases. Hence, a catalyst with high activity toward methanol oxidation must also have high activity for CO oxidation.3 This activity is explained by some authors in terms of the so-cal...

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“…Up to now, the Pt-based catalysts modified by the second metal such as Ru, Sn, Pb, Rh and Mo [8][9][10][11][12] or metal oxides including SnO 2 , ZrO 2 , TiO 2 , RuO 2 -IrO 2 and WO 3 [13][14][15][16][17] have been extensively investigated. The second element acts as the bifunctional mechanism and the ligand effect.…”

Section: Introductionmentioning

confidence: 99%

The Promoting Effect of Europium on PtSn/C Catalyst for Ethanol Oxidation

2010

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Well‐dispersed PtSnEu/C and PtSn/C catalysts were prepared by the impregnation–reduction method using formic acid as a reductant and characterised by X‐ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersion X‐ray spectroscopy (EDX) and X‐ray photoelectron spectroscopy (XPS). The synthesised catalysts with different atomic ratios of Pt/Sn/Eu have the Pt face centered cubic (fcc) structure and their particle sizes are 3–4 nm. The PtSnEu/C catalyst is composed of many Pt (0), SnO2, Eu(OH)3, a small amount of Pt(II) and partly alloyed PtSn, but no metallic Eu. The electrochemical measurements indicate that in comparison with Pt3Sn1/C catalyst, the Pt3Sn1Eu1/C catalyst for ethanol oxidation has more negative onset potential, smaller apparent activation energy and lower electrochemical impedance so that it exhibits very high catalytic activity. Its peak current density increases by 135% and 40%, compared with Pt3Sn1/C and Pt1Ru1/C (JM) catalysts, respectively. This is because the Eu(OH)3 formed by adding Eu to PtSn/C catalyst can provide the OH group which is in favour of the removal of adsorbed intermediates and ethanol oxidation.

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Electrocatalytic oxidation of ethanol on Pt–Mo bimetallic electrodes in acid medium

Cited by 64 publications

References 36 publications

Enhancement of activity of PtRh nanoparticles towards oxidation of ethanol through modification with molybdenum oxide or tungsten oxide

Enhancement of activity of PtRh nanoparticles towards oxidation of ethanol through modification with molybdenum oxide or tungsten oxide

Study of the Electrochemical Activities of Mo-Modified Pt Catalysts, for Application as Anodes in Direct Methanol Fuel Cells: Effect of the Aggregation Route

The Promoting Effect of Europium on PtSn/C Catalyst for Ethanol Oxidation

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