Local reactivity of supported metal clusters: Pd n on Au(1 1 1)

Roudgar, Ata; Groß, Axel

doi:10.1016/j.susc.2004.04.032

Cited by 76 publications

(63 citation statements)

References 29 publications

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“…18c). If the Pt specific activity does not vary significantly with the potential cycling, and assuming a constant Tafel slope b of -120 mV/dec, the remaining Pt surface area after potential cycling can be estimated by using the expression: DE 1/2 = -b log(S Pt / S Pt0 ), where S Pt is the Pt surface area after cycling and S Pt0 is the initial Pt surface area [36]. For the loss in E 1/2 of 39 mV, the calculated value for the remaining active Pt surface area is 47% of the initial one.…”

Section: Stabilization Of Pt Orr Electrocatalysts Using Au Clusters-mmentioning

confidence: 99%

“…Roudgar and Groß [36] used DFT calculations to demonstrate a significant coupling of d-orbitals of small Pd clusters to the Au(111) substrate. An equivalent type of interaction between Au and Pt can account for the observed stabilization of Pt, which can become ''more noble'' through its interactions with Au.…”

Section: Stabilization Of Pt Orr Electrocatalysts Using Au Clusters-mmentioning

confidence: 99%

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Platinum Monolayer Fuel Cell Electrocatalysts

et al. 2007

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We describe a new class of electrocatalysts for the O 2 reduction, and H 2 and methanol oxidation reactions, consisting of a monolayer of Pt deposited on a metal or alloy carbon-supported nanoparticles. These electrocatalysts show up to a 20-fold increase in Pt mass activity compared with conventional all-Pt electrocatalysts. The origin of their increased activity was identified through a combination of experimental methods, employing electrochemical and surface science techniques, X-ray absorption spectroscopy, and density functional theory calculations. The long-term tests in fuel cells demonstrated excellent stability of the anode and good stability of the cathode electrocatalysts. We also describe the stabilization of Pt electrocatalysts against dissolution under potential cycling regimes effected by a submonolayer of Au clusters deposited on Pt surfaces. These new electrocatalysts promise to alleviate some of the major problems of existing fuel cell technology.

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Section: Stabilization Of Pt Orr Electrocatalysts Using Au Clusters-mmentioning

confidence: 99%

Section: Stabilization Of Pt Orr Electrocatalysts Using Au Clusters-mmentioning

confidence: 99%

Platinum Monolayer Fuel Cell Electrocatalysts

et al. 2007

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“…[46][47][48]50 Related to this work, Roudgar et al calculated that three-dimensional Pd 9 clusters on a Au(111) surface interact less strongly with adsorbates than a pseudomorphic Pd overlayer. [51][52][53] In the following, we will, after a brief description of the experimental set-up and procedures and computational details, first evaluate the structure of the PdAu-Pd(111) surface alloys, as derived from STM imaging (Section 3.1), then present TPD and HREELS measurements on different surface alloys (Section 3.2), and finally the results of the DFT calculations and their correlations with the experimental findings, in particular with the trends in adsorption energies on different PdAu nanostructures and their ability to adsorb hydrogen (Section 3.3). Here we will also discuss consequences of these findings for the understanding of hydrogen adsorption on bimetallic surfaces in general.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen adsorption on bimetallic PdAu(111) surface alloys: minimum adsorption ensemble, ligand and ensemble effects, and ensemble confinement

Takehiro

Liu

Bergbreiter

et al. 2014

Phys. Chem. Chem. Phys.

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The adsorption of hydrogen on structurally well defined PdAu-Pd(111) monolayer surface alloys was investigated in a combined experimental and theoretical study, aiming at a quantitative understanding of the adsorption and desorption properties of individual PdAu nanostructures. Combining the structural information obtained by high resolution scanning tunneling microscopy (STM), in particular on the abundance of specific adsorption ensembles at different Pd surface concentrations, with information on the adsorption properties derived from temperature programmed desorption (TPD) spectroscopy and high resolution electron energy loss spectroscopy (HREELS) provides conclusions on the minimum ensemble size for dissociative adsorption of hydrogen and on the adsorption energies on different sites active for adsorption. Density functional theory (DFT) based calculations give detailed insight into the physical effects underlying the observed adsorption behavior. Consequences of these findings for the understanding of hydrogen adsorption on bimetallic surfaces in general are discussed.

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“…The increasing undercoordination of surface atoms with decreasing particle size reduces the average bond strength; this effect competes with the impact of the lattice contraction, which enhances the average bond strength [89]. Figure 10.4 shows E coh j j as a function of z and e, E coh j j ¼ gð z; eÞ ð 10:8Þ…”

Section: Cohesive Energies Of Pt Nanoparticlesmentioning

confidence: 99%