Optical Properties and Chemical Ordering of Ag–Pt Nanoalloys: A Computational Study

Olobardi, Sofia; Vega, Lorena; Fortunelli, Alessandro; Stener, Mauro; Viñes, Francesc; Neyman, Konstantin M.

doi:10.1021/acs.jpcc.9b07382

Cited by 13 publications

(26 citation statements)

References 33 publications

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“…In the chemical ordering calculations in the larger NP 586 and NP 1289 models the last verifying step by exceedingly demanding DFT calculations was omitted, fully relying on the E TOP energies. Applications of this method [ 20 , 21 ] to various bimetallic NPs revealed that E TOP expressions despite their simplicity are sufficient for very efficient determining reliable atomic distributions in the energetically most stable homotops, in good agreement with DFT data [ 14 , 15 , 39 , 40 , 41 , 42 , 43 , 44 ].…”

Section: Computational Details and Modeling Approachmentioning

confidence: 92%

Pd Single-Atom Sites on the Surface of PdAu Nanoparticles: A DFT-Based Topological Search for Suitable Compositions

et al. 2021

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Structure of model bimetallic PdAu nanoparticles is analyzed aiming to find Pd:Au ratios optimal for existence of Pd1 single-atom surface sites inside outer Au atomic shell. The analysis is performed using density-functional theory (DFT) calculations and topological approach based on DFT-parameterized topological energy expression. The number of the surface Pd1 sites in the absence of adsorbates is calculated as a function of Pd concentration inside the particles. At low Pd contents none of the Pd atoms emerge on the surface in the lowest-energy chemical orderings. However, surface Pd1 sites become stable, when Pd content inside a Pd-Au particle reaches ca. 60%. Further Pd content increase up to almost pure Pd core is accompanied by increased concentration of surface Pd atoms, mostly as Pd1 sites, although larger Pd ensembles as dimers and linear trimers are formed as well. Analysis of the chemical orderings inside PdAu nanoparticles at different Pd contents revealed that enrichment of the subsurface shell by Pd with predominant occupation of its edge positions precedes emergence of Pd surface species.

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Section: Computational Details and Modeling Approachmentioning

confidence: 92%

Pd Single-Atom Sites on the Surface of PdAu Nanoparticles: A DFT-Based Topological Search for Suitable Compositions

et al. 2021

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“…The less intense stabilization of the ordered inner-phase L1 1 with increasing the NPs size is consistent with the reversed size-dependent stabilization of the L1 1 ordering observed for AgPt NPs. 16 However, stabilization of the L1 1 ordering with respect to LEH ones for AgPt NPs (see Table 2 for values and Figure S1 for structures) was calculated to be several times stronger, 17 indicating a notably decreased propensity of AgPd NPs to form the peculiar L1 1 ordering compared to analogous AgPt NPs.…”

Section: Resultsmentioning

confidence: 99%

“… d Number of homotops used in the fitting procedure to calculate the topological energy terms. e Values taken from ref ( 17 ). …”

Section: Resultsmentioning

confidence: 99%

“… c Quasi-perfect ordering, obtained from the perfect layered L1 1 homotop by swapping one pair of atoms Ax–Px. d Values taken from ref ( 17 ). …”

Section: Resultsmentioning

confidence: 99%

“…A computational modeling study by some of the authors of the present study dealt with the chemical ordering in AgPt NPs of increasing size at different compositions and revealed the favorable formation of the Ag shell. 17 There, systems with L1 1 - and L1 0 -ordered AgPt cores were modeled by 116-, 140- and 201-atom truncated octahedral crystallites with fcc structures.…”

Section: Introductionmentioning

confidence: 99%

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AgPd, AuPd, and AuPt Nanoalloys with Ag- or Au-Rich Compositions: Modeling Chemical Ordering and Optical Properties

et al. 2021

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Bimetallic nanoparticles have a myriad of technological applications, but investigations of their chemical and physical properties are precluded due to their structural complexity. Here, the chemical ordering and optical properties of AgPd, AuPd, and AuPt nanoparticles have been studied computationally. One of the main aims was to clarify whether layered ordered phases similar to L1 1 one observed in the core of AgPt nanoparticles [ Pirart J. Pirart J. 1982 31040272 Nat. Commun. 2019 10 ] are also stabilized in other nanoalloys of coinage metals with platinum-group metals, or the remarkable ordering is a peculiarity only of AgPt nanoparticles. Furthermore, the effects of different chemical orderings and compositions of the nanoalloys on their optical properties have been explored. Particles with a truncated octahedral geometry containing 201 and 405 atoms have been modeled. For each particle, the studied stoichiometries of the Ag- or Au-rich compositions, ca. 4:1 for 201-atomic particles and ca. 3:1 for 405-atomic particles, corresponded to the layered structures L1 1 and L1 0 inside the monatomic coinage-metal skins. Density functional theory (DFT) calculations combined with a recently developed topological (TOP) approach [ Kozlov S. M. Kozlov S. M. 29218158 Chem. Sci. 2015 6 3868 3880 ] have been performed to study the chemical ordering of the particles, whose optical properties have been investigated using the time-dependent DFT method. The obtained results revealed that the remarkable ordering L1 1 of inner atoms can be noticeably favored only in small AgPt particles and much less in AgPd ones, whereas this L1 1 ordering in analogous Au-containing nanoalloys is significantly less stable compared to other calculated lowest-energy orderings. Optical properties were found to be more dependent on the composition (concentration of two metals) than on the chemical ordering. Both Pt and Pd elements promote the quenching of the plasmon.

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Recent Developments in Plasmonic Alloy Nanoparticles: Synthesis, Modelling, Properties and Applications

2022

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Optical Properties and Chemical Ordering of Ag–Pt Nanoalloys: A Computational Study

Cited by 13 publications

References 33 publications

Pd Single-Atom Sites on the Surface of PdAu Nanoparticles: A DFT-Based Topological Search for Suitable Compositions

Pd Single-Atom Sites on the Surface of PdAu Nanoparticles: A DFT-Based Topological Search for Suitable Compositions

AgPd, AuPd, and AuPt Nanoalloys with Ag- or Au-Rich Compositions: Modeling Chemical Ordering and Optical Properties

Recent Developments in Plasmonic Alloy Nanoparticles: Synthesis, Modelling, Properties and Applications

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