Nanoporosity evolution during dealloying: Interplay between chemical dissolution, material defects, coarsening and local structural rearrangements over long timescales

Sandupatla, Aditya Shankar; Chatterjee, Abhijit

doi:10.1016/j.actamat.2021.116974

Cited by 6 publications

(7 citation statements)

References 57 publications

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“…The 18 nm particle contains 0.2 million atoms. Our state-of-the-art dealloying simulation captures multiscale phenomena in an unprecedented resolution from femtoseconds to over 1 h (real time) . We use the term extent of dissolution (EOD) for the fraction of Ag dissolved.…”

Section: Computational Methodologymentioning

confidence: 99%

“…Rates of dissolution of Ag, rates of diffusion of Au/Ag, KMC parameters, and classical MD simulation parameters were optimized in ref to match the dealloying of the Au–Ag alloy. The truncated octahedron nanoparticles are placed within a large cube-shaped supercell.…”

Section: Computational Methodologymentioning

confidence: 99%

“…The solvent water molecule is represented by a coarse-grained particle. The solvent influences the surface energy and controls the large-scale collapse of the NPG ligaments . In the absence of MD relaxation, the surface Ag concentration is low.…”

Section: Computational Methodologymentioning

confidence: 99%

“…As already identified in ref , the effect of adsorbed O is missing in MD. It is believed that adsorbed O can cause Ag to segregate to the surface.…”

Section: Computational Methodologymentioning

confidence: 99%

“…41 In our recent work, we introduced a multiscale modeling framework for simulating the dynamical dealloying process to accurately generate atomistically resolved NPG structures as Ag is dissolved from a Au−Ag alloy. 42 The framework involves a combination of lattice kinetic Monte Carlo (KMC) and molecular dynamics (MD) calculations to capture various physical and chemical processes fundamental to selective dissolution. The combination of KMC and MD is required because selective dissolution is inherently multiscale in nature.…”

Section: Introductionmentioning

confidence: 99%

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How the Facet Edge Controls the Overall CO Oxidation in Nanoporous Gold: Combined Atomistic Characterization/DFT Study of Residual Ag Distribution and Catalytic Activity

Sandupatla

Rana

et al. 2022

ACS Catal.

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Nanoporous gold (NPG) formed via dealloying/selective dissolution of the Au−Ag alloy is known to be catalytically active toward CO oxidation reaction (COR) even at room temperature. The atomistically resolved NPG structure is obtained by simulating the dealloying of Au 25 Ag 75 nanoparticles using a combination of kinetic Monte Carlo and molecular dynamics. The effect of adsorbed O is included. The experiment-like NPG structures from these computer simulations are characterized. We map the surface of NPG, determine the diverse binding sites, and assess their role in catalyzing the COR. Local surface Ag composition, population density of undercoordinated Au/Ag atoms, and cluster size distribution of surface Ag atoms are measured. A high density of dislocation defects is found in the simulated structure. The rate-determining steps, namely, O 2 binding and dissociation, are probed using density functional theory. We conclude that O 2 binding/dissociation is facilitated at the facet edge. Residual Ag at the edge aids in the capture of O 2 . Subsequently, O 2 dissociates after spilling over to Au sites at the facet edge. These conclusions are confirmed by showing that the normalized facet edge length of NPG and supported Au nanoparticles is linearly correlated to the experimental turnover frequency.

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Section: Computational Methodologymentioning

confidence: 99%

Section: Computational Methodologymentioning

confidence: 99%

Section: Computational Methodologymentioning

confidence: 99%

“…As already identified in ref , the effect of adsorbed O is missing in MD. It is believed that adsorbed O can cause Ag to segregate to the surface.…”

Section: Computational Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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