The Oxidation Behaviour of Ruthenium in the Presence of Platinum and its Effect on the Electrocatalytic Activity of Pt-Ru Fuel Cell Catalysts

Roth, Christina; Benker, Nathalie; Zils, Susanne; Chenitz, Régis; Issanin, Alexander; Fueß, H.

doi:10.1524/zpch.2007.221.11-12.1549

Cited by 5 publications

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“…Phys., 2011, 13, 6784-6792 6789 potentials for catalyst III indicates that poisoning of the catalyst during alcohol oxidation is quite small compared to the other catalysts as reported in the literature. 45 As discussed in the XRD section, the most active catalyst was catalyst III in which the large amount (more than 90%) of PtRu alloy formation was observed. This explains why the methanol and ethanol oxidation reactions take place at low potentials and high current density in catalyst III.…”

Section: Resultsmentioning

confidence: 91%

Preparation and characterization of nano-sized Pt–Ru/C catalysts and their superior catalytic activities for methanol and ethanol oxidation

Şen

Gökağaç

2011

Phys. Chem. Chem. Phys.

110

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Carbon-supported PtRu nanoparticles (Ru/Pt: 0.25) were prepared by three different methods; simultaneous reduction of PtCl(4) and RuCl(3) (catalyst I) and changing the reduction order of PtCl(4) and RuCl(3) (catalysts II and III) to enhance the performance of the anodic catalysts for methanol and ethanol oxidation. Structure, microstructure and surface characterizations of all the catalysts were carried out by X-ray diffraction (XRD), transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The results of the XRD analysis showed that all catalysts had a face-centered cubic (fcc) structure with different and smaller lattice parameters than that of pure platinum, showing that the Ru incorporates into the Pt fcc structure by different ratios in all the catalysts. The typical particle sizes of all catalysts were in the range of 2-3 nm. The most active and stable catalyst for methanol and ethanol oxidation is catalyst III, in which a large amount (more than 90%) of PtRu alloy formation was observed. It has been found that this catalyst is about 8.0 and 33.4 times more active at ∼0.60 V towards the methanol and ethanol oxidation reactions, respectively, compared to the commercial Pt catalyst.

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Section: Resultsmentioning

confidence: 91%

Preparation and characterization of nano-sized Pt–Ru/C catalysts and their superior catalytic activities for methanol and ethanol oxidation

Şen

Gökağaç

2011

Phys. Chem. Chem. Phys.

110

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“…The authors suggested that general surface oxidation and the lack of reactivity of ruthenium oxides prevent significant MOR activity. Surface oxidation should affect the ligand-stabilized and spontaneously deposited Ru nanoparticles used in this work much less than for bulk Ru, as both the surfactant shell and the presence of Pt at nearby ruthenium sites reduce the sensitivity toward surface oxide formation . This might explain the weak but clearly visible peak observed for the Ru sites.…”

Section: Resultsmentioning

confidence: 96%

“…In contrast, the latter might be more prone to ruthenium oxide formation or other deactivation processes than the ligand-stabilized nanoparticles since these are not protected by a surfactant shell. The reasons for the observed behavior are not completely understood, but the reduction of Ru−OH species in the presence of Pt in proximity to Ru seems to play an important role here …”

Section: Resultsmentioning

confidence: 99%

Bifunctional Electrocatalysis in Pt−Ru Nanoparticle Systems

et al. 2008

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Pt-Ru alloys are prominent electrocatalysts in fuel cell anodes as they feature a very high activity for the oxidation of reformate and methanol. The improved CO tolerance of these alloys has been discussed in relation to the so-called ligand and bifunctional mechanisms. Although these effects have been known for many years, they are still not completely understood. A new approach that bridges the gap between single crystals and practical catalysts is presented in this paper. Nanoparticulate model systems attached to an oxidized glassy carbon electrode were prepared by combining both ligand-stabilized and spontaneously deposited Pt and Ru nanoparticles. These electrodes showed very different voltammetric responses for CO and methanol oxidation. The cyclic voltammograms were deconvoluted into contributions attributed to Pt, Ru, and Pt-Ru contact regions to quantify the contribution of the latter to the bifunctional mechanism. Scanning transmission electron microscopy confirmed the proximity of Pt and Ru nanoparticles in the different samples.

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“…Another major issue is that once the platinum catalyst is exposed to trace fuel impurities or air pollutants such as carbon monoxide or organic chemical vapors, the catalytic surface of the platinum passivates making it unable to further catalyze the necessary reactions. Alloys of platinum with other metals such as cobalt, ruthenium, iron, and tin have been created that help maintain the catalytic ability and allow for more tolerance of these catalyst poisons, but these catalysts still contain a large amount of costly precious metal ,,− .…”

Section: Introductionmentioning

confidence: 99%

Growth of Phthalocyanine Doped and Undoped Nanotubes Using Mild Synthesis Conditions for Development of Novel Oxygen Reduction Catalysts

Arechederra

Artyushkova

Atanassov

2010

ACS Appl. Mater. Interfaces

114

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Precious metal alloys have been the predominant electrocatalyst used for oxygen reduction in fuel cells since the 1960s. Although performance of these catalysts is high, they do have drawbacks. The two main problems with precious metal alloys are catalyst passivation and cost. This is why new novel catalysts are being developed and employed for oxygen reduction. This paper details the low temperature solvothermal synthesis and characterization of carbon nanotubes that have been doped with both iron and cobalt centered phthalocyanine. The synthesis is a novel low-temperature, supercritical solvent synthesis that reduces halocarbons to form a metal chloride byproduct and carbon nanotubes. Perchlorinated phthalocyanine was added to the nanotube synthesis to incorporate the phthalocyanine structure into the graphene sheets of the nanotubes to produce doped nanotubes that have the catalytic oxygen reduction capabilities of the metallo-phthalocyanine and the advantageous material qualities of carbon nanotubes. The cobalt phthalocyanine doped carbon nanotubes showed a half wave oxygen reduction potential of -0.050 ± 0.005 V vs Hg\HgO, in comparison to platinum's half wave oxygen reduction potential of -0.197 ± 0.002 V vs Hg\HgO.

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The Oxidation Behaviour of Ruthenium in the Presence of Platinum and its Effect on the Electrocatalytic Activity of Pt-Ru Fuel Cell Catalysts

Cited by 5 publications

References 0 publications

Preparation and characterization of nano-sized Pt–Ru/C catalysts and their superior catalytic activities for methanol and ethanol oxidation

Preparation and characterization of nano-sized Pt–Ru/C catalysts and their superior catalytic activities for methanol and ethanol oxidation

Bifunctional Electrocatalysis in Pt−Ru Nanoparticle Systems

Growth of Phthalocyanine Doped and Undoped Nanotubes Using Mild Synthesis Conditions for Development of Novel Oxygen Reduction Catalysts

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