Exploring the Structure–Activity Relationship on Platinum Nanoparticles

Braunwarth, Laura; Jung, Christoph; Jacob, Timo

doi:10.1007/s11244-020-01324-w

Cited by 10 publications

(10 citation statements)

References 45 publications

(57 reference statements)

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“…This observation highlights the importance of taking both geometrical and electronic effects into account when studying reactivity trends in catalysis. 34 Beyond the clean particle, surface oxide, and fully oxidized ([Pt 6 O 8 ] n ) phases in the electrochemical phase diagrams, a fourth phase representing the bulk oxide, α-PtO 2 , would technically be expected. Note that α−PtO 2 (i.e.…”

Section: Discussionmentioning

confidence: 99%

Simulations of the Oxidation and Degradation of Platinum Electrocatalysts

Kirchhoff

Braunwarth

Jung

et al. 2019

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Improved understanding of the fundamental processes leading to degradation of platinum nanoparticle electrocatalysts is essential to the continued advancement of their catalytic activity and stability. To this end, the oxidation of platinum nanoparticles is simulated using a ReaxFF reactive force field within a grand-canonical Monte Carlo scheme. 2-4 nm cuboctahedral particles serve as model systems, for which electrochemical potential-dependent phase diagrams are constructed from the thermodynamically most stable oxide structures, including solvation and thermochemical contributions. Calculations in this study suggest that surface oxide structures should become thermodynamically stable at voltages around 0.80-0.85 V versus standard hydrogen electrode, which corresponds to typical fuel cell operating conditions. The potential presence of a surface oxide during catalysis is usually not accounted for in theoretical studies of Pt electrocatalysts. Beyond 1.1 V, fragmentation of the catalyst particles into [Pt 6 O 8 ] 4− clusters is observed. Density functional theory calculations confirm that [Pt 6 O 8 ] 4− is indeed stable and hydrophilic. These results suggest that the formation of [Pt 6 O 8 ] 4− may play an important role in platinum catalyst degradation as well as the electromotoric transport of Pt 2+/4+ ions in fuel cells.

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Section: Discussionmentioning

confidence: 99%

Simulations of the Oxidation and Degradation of Platinum Electrocatalysts

Kirchhoff

Braunwarth

Jung

et al. 2019

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“…Besides, force fields typically fail to describe bond-breaking and bond-making processes. Reactive force fields based on bond-order concepts are free from this restriction, but they require a considerable fitting effort and are therefore typically restricted to a small number of elements. , On the other hand, interpolation schemes including many-body effects such as the embedded atom method (EAM) , are appropriate for simple metals but cannot appropriately reproduce covalent bonding.…”

Section: Theoretical Description Of the Water–water And Water–metal I...mentioning

confidence: 99%

Ab Initio Simulations of Water/Metal Interfaces

2022

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Structures and processes at water/metal interfaces play an important technological role in electrochemical energy conversion and storage, photoconversion, sensors, and corrosion, just to name a few. However, they are also of fundamental significance as a model system for the study of solid–liquid interfaces, which requires combining concepts from the chemistry and physics of crystalline materials and liquids. Particularly interesting is the fact that the water–water and water–metal interactions are of similar strength so that the structures at water/metal interfaces result from a competition between these comparable interactions. Because water is a polar molecule and water and metal surfaces are both polarizable, explicit consideration of the electronic degrees of freedom at water/metal interfaces is mandatory. In principle, ab initio molecular dynamics simulations are thus the method of choice to model water/metal interfaces, but they are computationally still rather demanding. Here, ab initio simulations of water/metal interfaces will be reviewed, starting from static systems such as the adsorption of single water molecules, water clusters, and icelike layers, followed by the properties of liquid water layers at metal surfaces. Technical issues such as the appropriate first-principles description of the water–water and water–metal interactions will be discussed, and electrochemical aspects will be addressed. Finally, more approximate but numerically less demanding approaches to treat water at metal surfaces from first-principles will be briefly discussed.

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“…They showed that such metal-adsorbate interactions diminish the nanoparticles' thermal stability against solid-solid and solid-liquid transitions. Similarly, Braunwarth et al [43] observed the long-term stability of Pt cubes solvated in water by means of a ReaxFF potential. The cubes underwent a strong restructuring into concave disordered cuboids after a few ns of simulation.…”

Section: Catalyst-solvent Interfacementioning

confidence: 84%

Realistic Modelling of Dynamics at Nanostructured Interfaces Relevant to Heterogeneous Catalysis

et al. 2022

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The focus of this short review is directed towards investigations of the dynamics of nanostructured metallic heterogeneous catalysts and the evolution of interfaces during reaction—namely, the metal–gas, metal–liquid, and metal–support interfaces. Indeed, it is of considerable interest to know how a metal catalyst surface responds to gas or liquid adsorption under reaction conditions, and how its structure and catalytic properties evolve as a function of its interaction with the support. This short review aims to offer the reader a birds-eye view of state-of-the-art methods that enable more realistic simulation of dynamical phenomena at nanostructured interfaces by exploiting resource-efficient methods and/or the development of computational hardware and software.

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Exploring the Structure–Activity Relationship on Platinum Nanoparticles

Cited by 10 publications

References 45 publications

Simulations of the Oxidation and Degradation of Platinum Electrocatalysts

Simulations of the Oxidation and Degradation of Platinum Electrocatalysts

Ab Initio Simulations of Water/Metal Interfaces

Realistic Modelling of Dynamics at Nanostructured Interfaces Relevant to Heterogeneous Catalysis

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