Characterization and PEMFC Testing of Pt[sub 1−x]M[sub x] (M=Ru,Mo,Co,Ta,Au,Sn) Anode Electrocatalyst Composition Spreads

Stevens, David A.; Rouleau, J. M.; Mar, R. E.; Bonakdarpour, Arman; Atanasoski, Radoslav; Schmoeckel, Alison K.; Debe, Mark K.; Dahn, J. R.

doi:10.1149/1.2724591

Cited by 56 publications

(62 citation statements)

References 50 publications

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“…Moreover, this shift becomes very high when gold appears at the catalyst surface. This result is in broad agreement with that of Stevens et al [24]. The presence of gold in AuPt clusters involves an increase of the d-orbital vacancy of platinum [16,25] leading to a decrease in the d-orbital back donation from platinum to unoccupied CO 2π* [12].…”

Section: Resultssupporting

confidence: 92%

“…The positive shift could mean that the presence of gold contributes to the reinforcement of the bond between CO and Pt. The small amount of adsorbed CO on gold [24] (for a high gold content catalyst) leads to isolation of platinum clusters. Consequently, all lateral repulsive interactions between CO molecules are decreased and the CO-Pt bond becomes stronger.…”

Section: Resultsmentioning

confidence: 99%

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Electrocatalytic Activity of Supported Au–Pt Nanoparticles for CO Oxidation and O2 Reduction in Alkaline Medium

et al. 2010

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Various Pt-and Au-based nanocatalysts prepared by water-in-oil microemulsion method were used to study CO stripping and the oxygen reduction reaction in alkaline medium. It was shown that the particle size increases with the amount of gold in the bimetallic composition, which could be explained by rapid reduction kinetic of gold salt in comparison to that observed with platinum one. This results in the faster formation of nuclei followed by a more rapid growth of the particles. Geometric effects responsible for strong adsorption of CO on high content gold-platinum nanoparticles are discussed as well as the appearing special feature of gold during CO stripping experiments. The absence of a prepeak potential on Au 70 Pt 30 /C nanoparticles could be due to a very small amount of weakly adsorbed CO on the surface. A CO-adsorbed layer seems to be so stable and compact that it does not present a formation of "holes" involving a low decrease in repulsive interactions between CO molecules and a shift of the main oxidation peak towards positive potentials. Moreover, the modification of the strength of the Pt-OH bond due to the presence of gold was described as well as the high catalytic activity of gold-based nanoparticles toward the oxygen reduction reaction in 0.1 M NaOH.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Electrocatalytic Activity of Supported Au–Pt Nanoparticles for CO Oxidation and O2 Reduction in Alkaline Medium

et al. 2010

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“…It was expected that the presence of gold would provide less d orbital back-donation and shift the polarization of CO 5σ orbital, therefore weakening the Pt-CO bond. 23,50,51 Our results suggest that the optimal surface composition of a Pt and Au alloy was approximately represented by sample S9 (58% Pt, 42% Au). Such a catalyst would allow for an approximately 40% reduction in Pt loading for a fuel cell catalyst while achieving resistance to poisoning without a significant decrease in activity.…”

Section: Resultsmentioning

confidence: 69%

Electrocatalytic Activity of Gold−Platinum Clusters for Low Temperature Fuel Cell Applications

et al. 2009

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The electrocatalytic activity of gold-platinum (Au-Pt) clusters was investigated in acidic and alkaline electrolytes. The clusters were synthesized by electrodeposition on fluorinated tin oxide (FTO) substrates and carbon disks with dimensions from 50 to 200 nm. Methanol electrooxidation (fuel cell anode) and oxygen electroreduction (fuel cell cathode) activities were measured using cyclic voltammetry and chronoamperometry. The results for methanol electrooxidation showed that platinum could be partially substituted by gold to achieve higher resistance to poisoning without affecting the activity in acid electrolyte, while in alkaline environment, a significant overall improvement in performance was observed. On the other hand, for the oxygen electroreduction, kinetic results obtained using a rotating disk electrode (RDE) indicated that Au alloying with Pt does not significantly alter the catalytic activity in acidic electrolyte, while a significant improvement in activity was observed in an alkaline electrolyte, which is attributed to a synergistic effect between the Au and Pt.

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“…55%, although we would still expect some leaching for concentrations exceeding 25% for some elements. Dahn et al 13 studied a series of binary Pt anode electrocatalysts, including Ru, Mo, Co, Ta, Au, and Sn. They reported that both Mo and Co leached during electrochemical testing.…”

mentioning

confidence: 99%

High Throughput Thin Film Pt-M Alloys for Fuel Electrooxidation: Low Concentrations of M (M = Sn, Ta, W, Mo, Ru, Fe, In, Pd, Hf, Zn, Zr, Nb, Sc, Ni, Ti, V, Cr, Rh)

Tague

Gregoire

Legard

et al. 2012

J. Electrochem. Soc.

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Eighteen Pt-M binary (M = Sn, Ta, W, Mo, Ru, Fe, In, Pd, Hf, Zn, Zr, Nb, Sc, Ni, Ti, V, Cr, Rh) thin film composition spreads were deposited at low M concentrations using magnetron sputtering and screened for methanol and ethanol electrooxidation activity using a fluorescence assay. Characterization of these thin films was performed using high energy X-ray diffraction and X-ray fluorescence. The electrochemical fluorescence assay revealed highest activity in the films with M = Sn, Zn, In, Fe, and Ru. Pt-M (M = Sn, Zn, In) showed highest activity at concentrations below 5 atom-% with a high fraction of Pt fcc(111) texturing and Pt-Fe showing the best activity at 10 atom-% Fe. On the other hand, the best (most negative) fluorescence onset potential in the Pt-Ru system was observed at a concentration of 35 atom-% Ru with only slight texturing of the film. To explore the potential origins of the observed catalytic activity, preliminary calculations on the d-band center shift with alloying were performed for bulk concentrations of up to 30 atom-% for Fe and 16 atom-% for M = Sn, Zn.Fuel cells present a promising energy conversion technology that is not limited by the Carnot cycle efficiency. Fuel cell efficiencies can reach up to 80-90% whereas a typical Carnot engine can only reach a maximum efficiency of 45-50%. 1 Fuel cells, in principle, could provide higher efficiency, an environmentally friendly form of energy conversion and high power/energy density. While the ideal system is a hydrogen-oxygen proton exchange membrane fuel cell (PEMFC), transportation, storage, and widespread availability of hydrogen is challenging due to the required high pressures and low volumetric energy density when compared to other fuels. Methanol, ethanol, and other small organic molecules (SOMs) have the advantage of higher volumetric energy densities, easier transportation, and diversity of availability from biosources. 2 Present limitations for widespread deployment of fuel cells are the cathode and anode materials which are expensive, easily poisoned, and show degradation over time. For methanol and ethanol oxidation, the process is more complicated than in the case of hydrogen, since the carbon in the fuel must be oxidized to CO 2 for maximal efficiency. The catalyst must also exhibit high catalytic activity for fuel oxidation with minimal poisoning. Platinum is the most commonly used catalyst, but it is readily poisoned with even low (ppm) levels of CO. As CO stands as a general and ubiquitous intermediate in the oxidation of SOMs, different catalysts must be used/found. Many materials have been investigated as anode catalysts for the oxidation of methanol, ethanol, and ethylene glycol, including alloys, 3 intermetallics, 4 nonPt containing materials (carbides, nitrides, oxides), 5 and core-shell structures. 6 For the cathode case, Strasser et al. reported improved activity for oxygen reduction with a Pt shell and a Pt-Cu alloyed core when compared to Pt alone. 6a They also considered the improved activity to be a result of the...

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Characterization and PEMFC Testing of Pt[sub 1−x]M[sub x] (M=Ru,Mo,Co,Ta,Au,Sn) Anode Electrocatalyst Composition Spreads

Cited by 56 publications

References 50 publications

Electrocatalytic Activity of Supported Au–Pt Nanoparticles for CO Oxidation and O2 Reduction in Alkaline Medium

Electrocatalytic Activity of Supported Au–Pt Nanoparticles for CO Oxidation and O2 Reduction in Alkaline Medium

Electrocatalytic Activity of Gold−Platinum Clusters for Low Temperature Fuel Cell Applications

High Throughput Thin Film Pt-M Alloys for Fuel Electrooxidation: Low Concentrations of M (M = Sn, Ta, W, Mo, Ru, Fe, In, Pd, Hf, Zn, Zr, Nb, Sc, Ni, Ti, V, Cr, Rh)

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