PtRu carbon-supported

Gavrilov AN, Savinova ER, Simonov PA, Zaikovskii VI, Cherepanova SV, TsirUna GA, Parmon VN. 2007. On the irrfluence of the metal loading on the stmcture of carbon-supported PtRu catalysts and their electrocatal3ftic activities in CO and methanol electrooxidation. Phys Chem Chem Phys 9 5476-5489. 

Fig. 14.18 Cell potential at a current density of 350 mA cm 2 for a carbon-supported PtRu, a PtMo and a PtRu/PtMo bilayer anode. In the bilayer, PtRu is on the membrane side. (Originally published in C. J. M.

Carbon-supported Pt can also be used as the anode catalyst. However, this requires pure H2. Contaminants such as carbon monoxide (CO) poison the catalyst, because CO can strongly adsorb on Pt, blocking the catalytic sites and reducing platinum s catalytic activity. In H2 produced from the reforming of other fuels, CO is always present. Thus, to improve contaminant tolerance, carbon-supported PtRu was developed and now is always used as the anode catalyst. Ru can facilitate the oxidation of CO, releasing the catalytic sites on Pt through the following reactions ... 

Recent reports [22, 23] have demonstrated better CO tolerance with higher loadings (1-2 mg/cm ) PtRu catalysts in PEFC anodes, particularly at cell current densities lower than 200 mA/cm. In contrast, a thin-fihn anode catalyst of very low PtRu loading, prepared as a composite of carbon-supported PtRu (0.15 mg/cm ) and recast ionomer [14], did not exhibit lower losses when 5-20 ppm CO was introduced into the hydrogen feed stream [21]. The same PtRu catalyst was successful, however, in... 

Figure 14 shows the estimated average morphology of three different catalysts used to study the HOR in 100 ppm CO in a working fuel cell. As a plain Pt reference, a standard carbon-supported R catalyst from E-TEK (20 wt.% on Vulcan XC-72) was chosen and compared with both a traditional carbon-supported PtRu bimetallic electrocatalyst also from E-TEK (20 wt.% R Ru (1 1) on Vulcan XC-72 PtRu Alloy) as well as a so-called carbon-supported PtRu mixtrrre catalyst (PtRu Mix). The latter was produced by mechani-... 

Wang H, Alden LR, Di Salvo FJ, Abruna HD (2009) Methanol electrooxidation on PtRu bulk alloys and carbon-supported PtRu nanoparticle catalysts a quantitative OEMS study. Langmuir 25 7725-7735... 

Papageorgopoulos DC, de Heer MP, Keijzer M, Pieterse JAZ, de Bmijn FA. Nonalloyed carbon-supported PtRu catalysts for PEMFC applications. J Electrochem Soc 2004 151 A763-8. 

Carbon black was added to the solution and H2 was bubbled through it for complete reduction and formation of the carbon-supported PtRu alloys. PtRu alloy formation was proposed to have taken place, as TEM images of the formed nanosized particles indicated a face centered cubic structure (fee) rather than hexagonally closed packed (hep) structure typical for metallic Ru. 

Liu ZL, Lee JY, Chen WX, Han M, Gan LM. Ph5rsical and electrochemical characterizations of microwave-assisted polyol preparation of carbon-supported PtRu nanoparticles. Langmuir 2004 20 181-7. 

Deivaraj TC, Lee JY. Preparation of carbon-supported PtRu nanoparticles for direct methanol fuel cell applications - a comparative study. J Power Sources 2005 142 43-9. 

It has been found that the use of a second element wifli Pt, sueh as Ru, Sn, Co, Cr, Fe, Ni, Pd, Os, Mo, Mn, etc., in the form of an alloy or a co-deposit yields significant improvement in the CO-tolerance relative to pure Pt [29-38]. Among these various Pt-based binary systems, the most commonly used eatalyst is carbon-supported PtRu alloy (PtRu/C). This material is known to enhance CO tolerance, which can be ascribed to the electronic modification of Pt-Ru in PtRu alloys that decreases the CO binding energy on Pt and also binds OH strongly on the Ru active sites in the PtRu alloys [39]. Within this system, the performance of PEMFCs has been improved for fuel streams containing CO [40-42]. 

Under reformate-feed conditions, carbon-supported PtRu alloys are widely used as reasonably reformate-tolerant anode catalysts [254-257]. However, the CO toleranee of PtRu is still unsatisfactory for the higher CO concentrations expected at system start-up or during changes in load. Moreover, the limited availabihty of... 

Antolini E, Cardellini F. Formation of carbon supported PtRu alloys an XRD analysis. J Alloys Compd 2001 315 118-22. 

As the carbon-supported PtRu alloy catalyst seems the most practical for use in PEMFCs, many studies have investigated PtRu alloying with a third element, e.g., W, Mo, Sn, Mb, Au, Ag, Ir, Ni, in an attempt to further improve catalytic activity [21-25]. Some of the elements, such as W, Mo, Sn, Ir, andNi clearly show further improvement in activity due to flie co-catalytic effect, while other elements, such as Mb, Au, and Ag show no improvement but rather a negative effect CO/H2 electrooxidation activity. Furthermore, catalysts with different metal atomic ratios show unparallel activity toward CO/H2 electrooxidation. In summary, the... 

Alcaide, F, Alvarez, G., Tsiouvaras, N., Pena, M.A., Fierro, J.L. Martlnez-Huerta, M.V Electrooxidation of H2/CO on carbon-supported PtRu-MoOx nanoparticles for polymer electrolyte fuel-cells. Ini. J. Hydrogen Energy 36 (2011), pp. 14590-14598. 

In comparison with the extensive research and development of catalysts for PEMFC and DMFC, the development of catalysts for DEFCs has drawn a surge of interest recently in recent years due to its bio-fuel characteristic, its ability to eliminate the toxicity issue of methanol as in direct methanol fuel cells, and its high energy density. Carbon-supported PtRu, a well-known catalyst for DMFCs, was naturally studied for DEFCs [59], but lacks high activity for ethanol oxidation due to a high propensity of Ru to form RuOH at the oxidation potential region. 

Takasu, Y., Fujiwara, T., Murakami, Y., Sasaki, K., Oguri, M., Asaki, T., and Sugimoto, W. (2000) Effect of structure of carbon-supported PtRu electrocatalysts on the electrochemical oxidation of methanol. Journal of the Electrochemical Society, 147 (12), 4421 27. 

PtRu is the effective electrocatalyst for methanol oxidation reaction and the dispersion of the metal particles is of great importance for the utilization and activity, so we also compare several methods for the preparation of carbon-supported PtRu catalyst Similar to the reasons mentioned in Section 10.2.1 for Pt/C, high metal loadings are required for the PtRu/C catalyst We use 20wt Pt% —lOwt % Ru/C as an... 

Maris, E.P, Ketchie, W.C., Murayama, M., et al., 2007. Glycerol hydrogenolysis on carbon-supported PtRu and AuRu bimetallic catalysts. Journal of Catalysis 251,281-294. 

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