Structural effects on trends in the deposition and dissolution of metal-supported metal adstructures

Greeley, Jeffrey

doi:10.1016/j.electacta.2010.04.055

Cited by 67 publications

(67 citation statements)

References 43 publications

(52 reference statements)

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“…For instance, Pt on FeAu/C only lost $7% of its initial ORR activity when cycled 60 000 times between 0.6 and 1.1 V in an RDE experiment; 179 Pt on AuPd/C only lost 37% of its initial ORR activity when cycled 100 000 times between 0.6 and 1 V in a PEMFC. 181 The high stability of these catalysts could be due to (a) the decoration of steps or other defects on Pt with Au, preventing their dissolution, 141 (b) that subsurface oxide formation is inhibited by the presence of Au or Ir in the subsurface layer 179,184 and (c) the dissolution of Pd from the core, causing a contraction of the Pt overlayer and a decreased propensity towards dissolution. 181 Future progress in the development of these novel nanostructures would be to substantially increase their mass activity, normalised to total platinum group metal content (rather than the platinum metal content), and to prepare them using a synthesis method amenable towards industrial scale-up.…”

Section: Strategies To Improve the Performance Of Pt-alloy Nanoparticlesmentioning

confidence: 99%

“…Such roughening is likely to have an autocatalytic effect upon the corrosion of Pt, due to the increased susceptibility of undercoordinated sites towards dissolution. 141 The STM experiments described above were conducted upon single crystals in liquid electrolytes. Nonetheless, we anticipate that the enhanced dissolution of Pt nanoparticles in a fuel cell upon cycling could also be related to surface deformation at high O* coverages and subsurface oxide formation.…”

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confidence: 99%

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Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

Stephens

Bondarenko

Grønbjerg

et al. 2012

Energy Environ. Sci.

1,070

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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Section: Strategies To Improve the Performance Of Pt-alloy Nanoparticlesmentioning

confidence: 99%

mentioning

confidence: 99%

Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

Stephens

Bondarenko

Grønbjerg

et al. 2012

Energy Environ. Sci.

1,070

1,024

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“…22,23 We first introduce two different models for zinc dissolution, then we use a simple method to account for a finite bias and finally we show that there is a very small overpotential for this reaction. Although dissolution processes have been previously successfully studied with DFT [24][25][26] this is, to the best of our knowledge, the first attempt to model the electrochemical dissolution of zinc using DFT.…”

Section: Introductionmentioning

confidence: 99%

First principles investigation of zinc-anode dissolution in zinc–air batteries

Siahrostami

Tripković

Lundgaard

et al. 2013

Phys. Chem. Chem. Phys.

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aWith surging interest in high energy density batteries, much attention has recently been devoted to metal-air batteries. The zinc-air battery has been known for more than a hundred years and is commercially available as a primary battery, but recharging has remained elusive, in part because the fundamental mechanisms still remain to be fully understood. Here, we present a density functional theory investigation of the zinc dissolution (oxidation) on the anode side in the zinc-air battery. Two models are envisaged, the most stable (0001) surface and a kink surface. The kink model proves to be more accurate as it brings about some important features of bulk dissolution and yields results in good agreement with experiments. From the adsorption energies of hydroxyl species and experimental values, we construct a free energy diagram and confirm that there is a small overpotential associated with the reaction. The applied methodology provides new insight into computational modelling and design of secondary metal-air batteries.

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“…[8][9][10][11][12][13][14] Simultaneously, the theoretical aspects of UPD have been studied from first principles in an effort to connect calculated adsorption energies and model surface structures to experimentally measured underpotential shifts. 10,[15][16][17][18][19][20][21][22][23] For a thorough overview of the modeling of UPD phenomena, we direct the reader to the review by Sudha and Sangaranarayanan as well as a more recent review by Oviedo and co-workers. 24,25 The application of first-principles density functional theory (DFT) to model UPD has in several cases been met with great success while simultaneously yielding several perplexing inaccuracies.…”

Section: Introductionmentioning

confidence: 99%

“…One such challenging case to model is the UPD of copper onto the low index surfaces of gold in sulfuric acid media. 20,21,23 While the copper-gold-sulfate system is perhaps one of the most well experimentally characterized UPD couples, first-principles calculations that are performed in vacuum predict copper to desorb at overpotentials, thereby underestimating the voltage-dependent stability of the copper adlayer on gold electrodes. 19,21 Recently, a growing consensus has appeared in the literature that it is necessary to account for the adsorption of anions to accurately model the stability of metal atoms at the electrode surface.…”

Section: Introductionmentioning

confidence: 99%

Quantum–continuum simulation of underpotential deposition at electrified metal–solution interfaces

2017

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The underpotential deposition of transition metal ions is a critical step in many electrosynthetic approaches. While underpotential deposition has been intensively studied at the atomic level, first-principles calculations in vacuum can strongly underestimate the stability of underpotentially deposited metals. It has been shown recently that the consideration of co-adsorbed anions can deliver more reliable descriptions of underpotential deposition reactions; however, the influence of additional key environmental factors such as the electrification of the interface under applied voltage and the activities of the ions in solution have yet to be investigated. In this work, copper underpotential deposition on gold is studied under realistic electrochemical conditions using a quantum-continuum model of the electrochemical interface. We report here on the influence of surface electrification, concentration effects, and anion co-adsorption on the stability of the copper underpotential deposition layer on the gold (100) surface.npj Computational Materials (2017) 3:1 ; doi:10.1038/s41524-016-0004-9 INTRODUCTION Underpotential deposition (UPD) has played an increasingly important role in the electrochemical preparation of nanomaterials with atomically thin metal film coatings for catalysis, imaging, and sensing applications.1-6 The UPD process is characterized by the formation of a (sub)monolayer of metal ions on a more noble metal substrate in a voltage range more positive than the reversible reduction potential of the adsorbing ion. The voltage at which the adlayer desorbs from the surface during an anodic scan is typically referenced to the bulk stripping potential of the adsorbed metal film and is termed the underpotential shift (ΔΦ upd ). Kolb and co-workers correlated underpotential shifts with differences in work functions of the substrate and the depositing metal (Fig. 1), suggesting that a charge transfer between the adlayer and the substrate may account for the larger adsorption energy of the adatom on the foreign surface.7 Since their seminal work, numerous studies have been performed in an effort to characterize a wide variety of UPD couples with the aim of understanding the voltammetric dependence of the formation and stability of the UPD layer in addition to its composition and surface structure. [8][9][10][11][12][13][14] Simultaneously, the theoretical aspects of UPD have been studied from first principles in an effort to connect calculated adsorption energies and model surface structures to experimentally measured underpotential shifts.10,15-23 For a thorough overview of the modeling of UPD phenomena, we direct the reader to the review by Sudha and Sangaranarayanan as well as a more recent review by Oviedo and co-workers.

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Structural effects on trends in the deposition and dissolution of metal-supported metal adstructures

Cited by 67 publications

References 43 publications

Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

Understanding the electrocatalysis of oxygen reduction on platinum and its alloys

First principles investigation of zinc-anode dissolution in zinc–air batteries

Quantum–continuum simulation of underpotential deposition at electrified metal–solution interfaces

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