Water bilayer on the Pd/Au(111) overlayer system: Coadsorption and electric field effects

Roudgar, Ata; Groß, Axel

doi:10.1016/j.cplett.2005.04.103

Cited by 114 publications

(113 citation statements)

References 33 publications

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“…58 This was attributed to the hydrogen-down configuration being energetically more stable than any other orientation of molecule. 59,60 Similarly, a relatively small positive peak follows a negative dip located near h = d (near the tip). This suggests that water molecules near the tip orient preferentially so that the hydrogen atoms are closer to the tip (here, the hydrogen up orientation is preferred).…”

Section: Resultsmentioning

confidence: 99%

Monte Carlo Study on the Water Meniscus Condensation and Capillary Force in Atomic Force Microscopy

2012

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The water meniscus condensed between a nanoscale tip and an atomically flat gold surface was examined under humid conditions using grand canonical Monte Carlo simulations. The molecular structure of the meniscus was investigated with particular focus on its width and stability. The capillary force due to the meniscus showed a dampened oscillation with increasing separation between the tip and surface because of the formation and destruction of water layers. The layering of water between the tip and the surface was different from that of the water confined between two plates. The humidity dependence of the capillary force exhibited a crossover behavior with increasing humidity, which is in agreement with the typical atomic force microscopy experiment on a hydrophilic surface.

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Section: Resultsmentioning

confidence: 99%

Monte Carlo Study on the Water Meniscus Condensation and Capillary Force in Atomic Force Microscopy

2012

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“…The eect of the electric eld at the surface is taken into account. The simplest estimate involves introducing an external sawtooth potential with a potential drop in the vacuum, hence creating an electric eld at the surface [30,41,42,43]. This eld interacts with the dipole moment of the adsorbed species.…”

Section: Electrochemical Reactionsmentioning

confidence: 99%

A theoretical evaluation of possible transition metal electro-catalysts for N₂reduction

Skúlason

Bligaard

Guðmundsdóttir

et al. 2012

Phys. Chem. Chem. Phys.

1,250

1,468

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Theoretical studies of the possibility of forming ammonia electrochemically at ambient temperature and pressure are presented. Density functional theory calculations were used in combination with the computational standard hydrogen electrode to calculate the free energy prole for the reduction of N 2 admolecules and N adatoms on several close-packed and stepped transition metal surfaces in contact with an acidic electrolyte. Trends in the catalytic activity were calculated for a range of transition metal surfaces and applied potentials under the assumption that the activation energy barrier scales with the free energy dierence in each elementary step. The most active surfaces, on top of the volcano diagrams, are Mo, Fe, Rh, and Ru, but hydrogen gas formation will be a competing reaction reducing the faradaic eciency for ammonia production. Since the early transition metal surfaces, such as Sc, Y, Ti, and Zr bind N-adatoms more strongly than H-adatoms, a signicant production of ammonia compared with hydrogen gas can be expected on those metal electrodes when a bias of -1 V to -1.5 V vs. SHE is applied. Defect-free surfaces of the early transition metals are catalytically more active than their stepped counterparts.

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“…42,43 The theoretical modelling of electrochemical reactions is equally complex, as it needs to account for the effect of the solvent on the adsorbed intermediates, the highly charged electric field in the double layer, the free energy of the electrons in the solid and the free energy of the solvated reactants as a function of potential. [44][45][46][47][48][49][50][51][52][53][54] However, it turns out that the overall trends can be 7 ‡ We note that a fuel cell would probably be operated at potentials lower than 0.9 V, to maximise the power output. However, catalysts are typically benchmarked at 0.9 V to minimise artefacts from the measurements.…”

Section: Theoretical Trends In Activity For Pt and Its Alloysmentioning

confidence: 99%

Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

Stephens

Bondarenko

Grønbjerg

et al. 2012

Energy Environ. Sci.

1,054

1,024

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The high cost of low temperature fuel cells is to a large part dictated by the high loading of Pt required to catalyse the oxygen reduction reaction (ORR). Arguably the most viable route to decrease the Pt loading, and to hence commercialise these devices, is to improve the ORR activity of Pt by alloying it with other metals. In this perspective paper we provide an overview of the fundamentals underlying the reduction of oxygen on platinum and its alloys. We also report the ORR activity of Pt 5 La for the first time, which shows a 3.5-to 4.5-fold improvement in activity over Pt in the range 0.9 to 0.87 V, respectively. We employ angle resolved X-ray photoelectron spectroscopy and density functional theory calculations to understand the activity of Pt 5 La.

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Water bilayer on the Pd/Au(111) overlayer system: Coadsorption and electric field effects

Cited by 114 publications

References 33 publications

Monte Carlo Study on the Water Meniscus Condensation and Capillary Force in Atomic Force Microscopy

Monte Carlo Study on the Water Meniscus Condensation and Capillary Force in Atomic Force Microscopy

A theoretical evaluation of possible transition metal electro-catalysts for N₂reduction

Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

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Water bilayer on the Pd/Au(111) overlayer system: Coadsorption and electric field effects

Cited by 114 publications

References 33 publications

Monte Carlo Study on the Water Meniscus Condensation and Capillary Force in Atomic Force Microscopy

Monte Carlo Study on the Water Meniscus Condensation and Capillary Force in Atomic Force Microscopy

A theoretical evaluation of possible transition metal electro-catalysts for N2reduction

Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

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Product

Resources

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A theoretical evaluation of possible transition metal electro-catalysts for N₂reduction