Role of surface composition in co adsorption on PdAg catalysts

Wise, Henry

doi:10.1016/0021-9517(76)90327-4

Cited by 6 publications

(2 citation statements)

References 6 publications

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“…Alloying nonadsorbing or weakly adsorbing components can modify the nature of the adsorbed CO by modifying the electronic structure ͑filling of d orbit-als͒ as observed with Pt-Sn alloys 20 and by introducing a stearic or ensemble effect as observed with Pd-Ag alloys. 21 The nature of CO adsorption on Pt and Pd was modified from bridged to linearly bonded CO by the addition of Sn and Ag, respectively.…”

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confidence: 99%

Development of New CO Tolerant Ternary Anode Catalysts for Proton Exchange Membrane Fuel Cells

Venkataraman

Kunz

Fenton

2003

J. Electrochem. Soc.

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Four ternary catalysts, Pt-Ag-Ru, Pt-Au-Ru, Pt-Rh-Ru, and Pt-Ru-W 2 C, were investigated as anode electrocatalysts for oxidation of hydrogen-containing carbon monoxide. These catalysts were either alloys or intimate admixtures of the components. Membrane electrode assemblies were prepared for all the catalysts with anode Pt loading of 0.4 mg/cm 2 , and anode polarization was determined for oxidation of a H 2 stream containing 104 ppm CO. Potentials for CO oxidation were determined by stripping preadsorbed CO using cyclic voltammetry. The Pt-Ru-W 2 C ͑1:1:0.4 molar ratio͒ oxidizes CO at a lower potential, and the polarization for oxidation of hydrogen-containing CO was lower than the widely used Pt-Ru ͑1:1 molar ratio͒ catalyst. At low polarization, the Pt-Ru-W 2 C catalyst showed twice the activity of the Pt-Ru catalyst when the oxidation currents were normalized to the Pt area.

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confidence: 99%

Development of New CO Tolerant Ternary Anode Catalysts for Proton Exchange Membrane Fuel Cells

Venkataraman

Kunz

Fenton

2003

J. Electrochem. Soc.

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“…Some of the alloy catalysts can free the Pt surface by catalyzing the oxidation of CO at potentials much lower than those observed for Pt (bifunctional effects). A typical example is a Pt-Ru alloy catalyst with a 1:1 atomic ratio [67,68]. Some other alloy catalysts, such as Pt-Ni and Pt-Fe, can also lower the adsorption of CO at the electrode surface by modifying the electronic structure (i.e., the ligand effect, which is illustrated in Figure 3.4) and thus suppressing CO coverage through alloying Pt with the second metal [69].…”

Section: Pt Alloy and Co-tolerant Catalystsmentioning

confidence: 99%

Electrocatalytic H2 Oxidation Reaction

Li¹,

Lee²,

Zhang³

PEM Fuel Cell Electrocatalysts and Catalyst Layers

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Hydrogen (H 2 ), an important material and product in chemical industries, has been investigated as a new clean energy source for many decades [1][2][3]. With the rapid development of proton exchange membrane (PEM) fuel cell technology, in which H 2 is used as a fuel, the chemical energy stored in this H 2 can be electrochemically converted to electric energy with zero emissions and high efficiency. The dream of a hydrogen economy era therefore seems closer to reality. Beginning in the 1990s, the advantages of PEM fuel cells, including zero/low emissions, high energy efficiency, and high power density, have attracted world-wide research and development in several important application areas, including automotive engines, stationary power generation stations, and portable power devices [4]. With successful demonstrations of fuel cell technology, in particular in automotive applications, commercialization of this technology has become a strong driving force for further development in the critical areas of cost reduction and durability. The major cost of a PEM fuel cell is the platinum (Pt)-based catalysts. At our current technological stage, these Pt-based catalysts for both the cathodic O 2 reduction reaction (ORR) and the anodic H 2 oxidation reaction (HOR) are the most practical catalysts in terms of catalytic activity and lifetime stability. Therefore, research and development to improve catalytic activity and stability has shot to the fore in recent years. Although both theoretical and experimental approaches have resulted in great progress in fuel cell catalysis [2,3,5,6], continuous effort is necessary to develop breakthrough fuel cell catalysts that are cost-effective and highly durable for commercial use.With respect to fuel cell catalysis, most research has been focused on cathode ORR catalysts development, because the ORR kinetics are much slower than the anodic HOR kinetics; in other words, the fuel cell voltage drop polarized by load is due mainly to the cathode ORR overpotential [7,8]. However, in some cases the overpotential of the anodic HOR can also contribute a non-negligible portion of the overall fuel cell voltage drop [8]. Therefore, the catalytic HOR on the fuel cell anode catalyst is also worth examining.

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