Au@void@AgAu YolkâShell Nanoparticles with Dominant Strain

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Au@void@AgAu Yolk-Shell Nanoparticles with Dominant Strain Effects: a Molecular Dynamics Simulation Hamed Akbarzadeh, Esmat Mehrjouei, Amir Nasser Shamkhali, Mohsen Abbaspour, Sirous Salemi, and Samira Ramezanzadeh J. Phys. Chem. Lett., Just Accepted Manuscript • DOI: 10.1021/acs.jpclett.7b02310 • Publication Date (Web): 29 Sep 2017 Downloaded from http://pubs.acs.org on October 1, 2017

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The Journal of Physical Chemistry Letters

Au@void@AgAu Yolk-Shell Nanoparticles with Dominant Strain Effects: a Molecular Dynamics Simulation Hamed Akbarzadeh a*, Esmat Mehrjouei a, Amir Nasser Shamkhali b, Mohsen Abbaspour a, Sirous Salemi a, Samira Ramezanzadeh a a) Department of Chemistry, Faculty of Basic Sciences, Hakim Sabzevari University, 9617976487Sabzevar, Iran b) Department of Chemistry, Faculty of Sciences, University of Mohaghegh Ardabili, 5619911367 Ardabil, Iran *Email: [email protected]

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Abstract In this investigation, Au@void@AgAu yolk-shell nanoparticles with different morphologies were studied by classical molecular dynamics simulation. The results indicated that all of simulated yolk-shell nanoclusters with approximately 3.8 nm size and different morphologies are unstable at room temperature and collapse of the shell atoms into the void space completely fills it and create more stable Au@AgAu core-shell structures. Also, it was observed that thermodynamic stabilities of the created core-shell structures are strongly depended on the morphology of nanocluster, for which competition between strain and surface energy effects plays the key role in this phenomenon. Within this competition, strain effect is dominant and helps to the stability of the created core-shell structure. Herein, the icosahedral nanocluster with the lowest strain effect exhibits the highest thermodynamic stability. By comparing the simulation results with experimental data, it was concluded that the essential factor which controls the stability of these nanoparticles is their size.


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Nano-sized materials have attracted a wide attention due to their potential applications1-5. At recent years, especially, gold and silver nanoparticles (NPs) have received considerable attention duo to their potential applications in many fields such as catalysis6-9, sensors10,11, optics12-16, electronics17-20, and medical researches

21

. It has been demonstrated that the intrinsic properties

of gold and silver nanoparticles such as surface plasmon resonance (SPR), surface enhanced Raman scattering (SERS), photonic, optical and catalytic activities are tunable by synthesizing these nanoparticles in the core-shell (Ag@Au or Au@Ag) geometry 22-25. Recently, various research groups have paid attention to a new type of Ag-Au core-shell structures, i.e. nanorattles or yolk-shell nanoparticles (YSNPs), with a core@void@shell configuration containing a hollow space between the core and outer shell 26-28. For example, Sun and co-workers, synthesized YSNPs with movable Au-Ag alloy cores inside of the Au-Ag alloy shells26. Cho and co-workers prepared Au@void@Ag YSNPs with an Au nanorod encapsulated inside of a silver nanocage based on the galvanic replacement reaction27. Currently, LondonoCalderon and co-workers, synthesized Au@void@AgAu yolk-shell cuboctahedra NPs with smooth open surface by using a combined seed mediated and galvanic replacement method. They also tested the catalytic activity of Au@void@AgAu NPs in the reduction of 4-nitrophenol by NaBH4 at room temperature28. It is expectable that Ag-Au YSNPs may demonstrate catalytic properties different than solid Ag-Au core-shell NPs. Despite of mentioned studies on synthesis and catalytic activity of YSNPs, there are few reports on the stability of YSNs. In our previous work, we investigated the effects of core and shell sizes on thermodynamic stability and melting behavior of Au@void@Ag YSNPs with an Au core and an Ag shell by molecular dynamics (MD) simulations. Our results showed that YSNPs with the largest core and shell (i.e. minimum void space) demonstrated the highest thermodynamic stability and melting point. In fact, we showed that the core and shell sizes affect on the stability and melting behavior of YSNPs, cooperatively29. Since, recent studies have exhibited that both of the structural and thermodynamic stabilities of bimetallic nanoclusters depend on their composition, size, and morphology 30-34, hence we believe that the mentioned factors may have a great effects on the stability of YSNPs, which are important for their potential application in catalysis and other fields of nanotechnology. Therefore, in this study, we focus on the understanding the relationship between morphology of YSNs and their stability.



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Herein, for the first time, we describe the stability of Au@void@AgAu YSNPs consisting of Au cores, Ag/Au disordered alloy shells, and an inner hollow space between the Au core and the alloy shell. Total sizes of the simulated nanoclusters were 3.8 nm, approximately. These nanoclusters were selected with several of morphologies including icosahedral (Ih), cuboctahedral (CO), decahedral (Dh), Marks-decahedral (m-Dh), and octahedral (Oh). Also, the same total number of atoms in the core and shell was considered. The mentioned nanoclusters were simulated using MD simulation method in canonical ensemble (NVT). The snapshots of structures of Au@void@AgAu YSNPs with various morphologies at 1 and 300 K are presented in Figure 1. MD simulations were performed by DL_POLY 4.03 software35. The temperature of the systems was controlled using Nosé-Hoover thermostat36,37. The equations of motion were integrated using Verlet-leapfrog algorithm38 with a time step of 1 fs. In order to study the stability of YSNPs, the temperature of the systems was varied from 1 to 300 K with rate of 50 K/ns. Then the properties of YSNPs with various morphologies were investigated at 300 K. The metal-metal interactions were modeled via the quantum Sutton-Chen (QSC) many body potential39,40. As it is obvious from Figure 1, especially in Figure 1(b), all of Au@void@AgAu nanoclusters with different morphologies are unstable at room temperature in such a way that Ag and Au atoms of the shell region are collapsed into the void space in order to increase their coordination number and creating more stable Au@AgAu core-shell (CS) structures. These results are in good agreement with our previous investigation on Au@void@Ag YSNPs for which it was indicated that they are unstable at temperatures lower than 350 K and the void space is completely filled near to this temperature 29. Another interesting result of Figure 1 is considerable retaining of the morphologies of the core and shell regions after collapse of Ag and Au atoms into the void space at 300 K for final core-shell structures in comparison with the initial YS ones. In order to better comparison of the created core-shell nanoclusters with different morphologies at room temperature, their ∆ parameters were calculated. This parameter is related to the excess energy of the nanocluster as 30,41:

∆ = where

E total − E bulk ( N tota l ) 2 / 3

(1)

Etot is the total energy of the nanocluster and Ebulk is the bulk energy which is given by: 4 ACS Paragon Plus Environment

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coh coh Ebulk = NAgε Ag + NAuε Au

(2)

co h where NAg and ε A g are the number of Ag atoms in the nanocluster and the cohesive energy of

bulk Ag atoms, respectively. NAu and

N to ta l = N

Ag

+ N

Au

coh ε Au have

the similar meanings for Au atoms.

is the total number of atoms in the nanocluster. It is noticeable that the

lower value of ∆ parameter demonstrates the more stable structure of the nanocluster. We have calculated the ∆ values for Au@void@AgAu YSNPs as a function of morphology at 300 K in Figure 2. By considering this figure, a Ih > m-Dh > CO > Dh > Oh trend is obtained for thermodynamic stabilities of the created core-shell structures, in such a way that at 300 K, Ih nanocluster exhibits the highest thermodynamic stability, while Oh nanocluster has the lowest stability. We also considered the surface energy of the Au@void@AgAu YSNPs as a function of morphology at 300 K in Figure 3. Surface energy is defined as the energy necessary to bring an atom to the surface, to form and maintain the surface area in equilibrium. Surface energy is also represented by the surface free energy per unit surface area in thermodynamics (the reversible work per unit area required to form a new surface of a substance)

42,43

. The surface energy is

calculated as44:

E surfa ce =

E P , cluster − E P , bu lk

(3)

Acluster

where EP,cluster is the potential energy of the nanocluster, EP,bulk is the potential energy of a bulk system containing the same number of atoms, and Acluster is the total nanocluster surface area. It is well-known that by decrease of the nanocluster surface energy, its thermodynamic stability is increased. However, this is not the case for the nanoclusters presented in Figure 2. It seems that Figure 3 shows a trend in opposite way in comparison with the trend of Figure 2. This means that Ih nanocluster with the highest thermodynamic stability has also the highest surface energy. This phenomenon seems to be more complicated. Therefore, it seems that considering strain effects can be helpful here. Strain effects are important for nanoalloys

45,46


. Figure 4 presents of atomic


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strain values for various morphologies studied in this work. Atomic strain is defined using the following equation 33:

δ =

∆r r0

(4)

where r0 is the diameter of the nanocluster in its minimum energy structure (i.e. the relaxed structure) and ∆r is the change in this dimension upon locating of the atoms in their ideal bulk positions. In Figure 4, the atoms have been arranged by their distance from center of the nanocluster. Also, the vertical dashed lines represent the core-shell interface, and the strain gap in this interface caused by existence of a surface tension between the core and the shell regions. Moreover, the horizontal dashed lines represent zero value for the strain. By considering Figure 4 it can be observed that strain values are different for various morphologies of the nanocluster. The central atoms undergo positive strain values for all of morphologies which mean existence of tensile strain in the core region. On the other hand, the shell atoms undergo average strain values which imply existence of compressive strain in the shell of nanocluster. Therefore, core atoms with expansion and shell atoms with contraction tend to occupation of the void space for all of the simulated morphologies which lead to creation of more stable core-shell nanoclusters. These results are more obvious in Figure 5. In this figure, red color represents strong positive strain, green color demonstrates the smaller positive strain, and blue color indicates the negative strain. It can be observed that for all of simulated nanoclusters, the central atoms are under tensile strain (smaller positive strain values) and the surface atoms are under compressive strain (negative strain values). The results of Figure 4 are in good agreement with those obtained from Figure 2, because for Ih nanocluster the range of strain values from negative to positive quantities is the least in comparison with the other ones. Therefore, it is expected that Ih nanocluster to exhibit the highest thermodynamic stability. Instead, Dh, and Oh nanoclusters with the broadest ranges of strain values exhibit the lowest thermodynamic stabilities. Hence, by considering the results of the simulations one can conclude that for all of the studied nanoclusters, there is a competition between the strain and the surface energy. However, within this competition, strain effect is dominant in such a way that by decrease of the internal pressure of the core region, overcomes on the surface energy effect in the shell region and helps to stability of the nanocluster. 6 ACS Paragon Plus Environment

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In summary, the results of MD simulations indicated that all of YS structures are unstable at 300 K and expansion of the core atoms and contraction of the shell ones leads to complete collapse of the void space and creation of the more stable core-shell NPs. However, Au@void@AgAu YSNPs synthesized by Calderon et al.28 were reported that are stable at room temperature. It is noticeable that their synthesized nanoclusters were much larger than the simulated ones in this work. Therefore, it can be concluded that the essential factor which controls stability of YSNPs is their size. Also, it was observed that the stabilities of the created core-shell NPs are depended on their morphologies, significantly. The competition between strain and surface energy plays the key role in thermodynamic stability of these NPs, in such a way that strain effect can overcome to this competition and leads to stability of the created nanocluster. On the basis of several studies, in addition to the size and composition, shape and morphologies of bimetallic nanoclusters affect on their catalytic activities, significantly. Therefore, the results of this study can provide useful information for synthesis and applications of YSNPs in various fields of nanotechnology.

References (1) Ataee‐Esfahani, H.; Imura, M.; Yamauchi, Y., All‐Metal Mesoporous Nanocolloids: Solution‐Phase Synthesis of Core–Shell Pd@ Pt Nanoparticles with a Designed Concave Surface. Angew. Chem. Int. Ed. 2013, 52, 13611–13615. (2) Jiang, B.; Li, C.; Tang, J.; Takei, T.; Kim, J. H.; Ide, Y.; Henzie, J.; Tominaka, S.; Yamauchi, Y., Tunable‐Sized Polymeric Micelles and Their Assembly for the Preparation of Large Mesoporous Platinum Nanoparticles. Angew. Chem. Int. Ed. 2016, 55, 10037–10041. (3) Malgras, V.; Ataee‐Esfahani, H.; Wang, H.; Jiang, B.; Li, C.; Wu, K. C. W.; Kim, J. H.; Yamauchi, Y., Nanoarchitectures for Mesoporous Metals. Adv. Mater. 2016, 28, 993– 1010. (4) Ferrando, R.; Jellinek, J.; Johnston, R. L. Nanoalloys: from Theory to Applications of Alloy Clusters and Nanoparticles. Chem. Rev. 2008, 108, 845–910. (5) Bulusu, S.; Li, X.; Wang, L. –S.; Zeng, X. C. Evidence of Hollow Golden Cages. Proc. Natl. Acad. Sci. 2006, 103, 8326–8330. 7 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(6) Gell,

L.;

Häkkinen,

H.

Theoretical

Analysis

of

the

Page 8 of 18

M12Ag32(Sr)404–

and

X@M12Ag32(Sr)304– Nanoclusters (M= Au, Ag; X= H, Mn). J. Phys. Chem. C 2014, 119, 10943–10948. (7) Burr, L.; Schubert, I.; Sigle, W.; Trautmann, C.; Toimil-Molares, M. E. Surface Enrichment in Au–Ag Alloy Nanowires and Investigation of the Dealloying Process. J. Phys. Chem. C, 2015, 119, 20949–20956. (8) Gould, A. L.; Logsdail, A. J.; Catlow, C. R. A. Influence of Composition and Chemical Arrangement on the Kinetic Stability of 147-Atom Au–Ag Bimetallic Nanoclusters. J. Phys. Chem. C 2015, 119, 23685–23697. (9) Wang, S.; Jin, S.; Yang, S.; Chen, S.; Song, Y.; Zhang, J.; Zhu, M. Total Structure Determination of Surface Doping [Ag46Au24(SR)32](BPh4)2 Nanocluster and its StructureRelated Catalytic Property. Sci. Adv. 2015, 1, e1500441. (10) Zheng, B.; Zheng, J.; Yu, T.; Sang, A.; Du, J.; Guo, Y.; Xiao, D.; Choi, M. M. Fast Microwave-Assisted Synthesis of AuAg Bimetallic Nanoclusters with Strong Yellow Emission and their Response to Mercury (II) Ions. Sens. Actuators B-Chem. 2015, 221, 386–392. (11) Manshina, A.; Grachova, E.; Povolotskiy, A.; Povolotckaia, A.; Petrov, Y. V.; Koshevoy, I.; Makarova, A.; Vyalikh, D.; Tunik, S. Laser-Induced Transformation of Supramolecular Complexes: Approach to Controlled Formation of Hybrid Multi-YolkShell Au-Ag@a-C:H Nanostructures. Sci. Rep. 2015, 5, 12027. (12) Jia, X.; Li, J.; Zhang, X.; Wang, E. Controlling the Synthesis and Assembly of Fluorescent Au/Ag Alloy Nanoclusters. Chem. Commun. 2015, 51, 17417–17419. (13) Cha, S. K.; Mun, J. H.; Chang, T.; Kim, S. Y.; Kim, J. Y.; Jin, H. M.; Lee, J. Y.; Shin, J.; Kim, K. H.; Kim, S. O. Au–Ag Core–Shell Nanoparticle Array by Block Copolymer Lithography for Synergistic Broadband Plasmonic Properties. ACS Nano 2015, 9, 5536– 5543. (14) Wu, Z.; Liu, J.; Gao, Y.; Liu, H.; Li, T.; Zou, H.; Wang, Z.; Zhang, K.; Wang, Y.; Zhang, H. Assembly-Induced Enhancement of Cu Nanoclusters Luminescence with Mechanochromic Property. J. Am. Chem. Soc. 2015, 137, 12906–12913. (15) Bhattacharyya, D.; Sarswat, P. K.; Islam, M.; Kumar, G.; Misra, M.; Free, M. L. Geometrical Modifications and Tuning of Optical and Surface Plasmon Resonance 8 ACS Paragon Plus Environment

Page 9 of 18

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Behaviour of Au and Ag Coated TiO2 Nanotubular Arrays. RSC Adv. 2015, 5, 70361– 70370. (16) Zhou, M.; Zhong, J.; Wang, S.; Guo, Q.; Zhu, M.; Pei, Y.; Xia, A. Ultrafast Relaxation Dynamics of Luminescent Rod-Shaped, Silver-Doped AgxAu25–x Clusters. J. Phys. Chem. C 2015, 119, 18790–18797. (17) Sun, J.; Yang, F.; Zhao, D.; Chen, C.; Yang, X. Integrated Logic Gate for Fluorescence Turn-on Detection of Histidine and Cysteine Based on Ag/Au Bimetallic Nanoclusters– Cu2+ Ensemble. ACS Appl. Mater. Interfaces 2015, 7, 6860–6866. (18) Seo, E.; Ko, S. –J.; Min, S. H.; Kim, J. Y.; Kim, B. –S. Plasmonic Transition via Interparticle Coupling of Au@Ag Core–Shell Nanostructures Sheathed in Double Hydrophilic Block Copolymer for High-Performance Polymer Solar Cell. Chem. Mater. 2015, 27, 4789–4798. (19) Cesca, T.; Kalinic, B.; Michieli, N.; Maurizio, C.; Trapananti, A.; Scian, C.; Battaglin, G.; Mazzoldi, P.; Mattei, G. Au–Ag Nanoalloy Molecule-Like Clusters for Enhanced Quantum Efficiency Emission of Er3+ Ions in Silica. Phys. Chem. Chem. Phys. 2015, 17, 28262–28269. (20) Munoz, F.; Varas, A.; Rogan, J.; Valdivia, J. A.; Kiwi, M. Au13−nAgn Clusters: A Remarkably Simple Trend. Phys. Chem. Chem. Phys. 2015, 17, 30492–30498. (21) Wang, P.; Lin, L.; Guo, Z.; Chen, J.; Tian, H.; Chen, X.; Yang, H. Highly Fluorescent Gene Carrier Based on Ag–Au Alloy Nanoclusters. Macromol. Biosci. 2016, 16, 160– 167. (22) Kreibig, U.; Bönnemann, H.; Hormes, J. Nanostructured Metal Clusters and Colloids. Handbook of surfaces and interfaces of materials 2001, 3, 1–85. (23) West, J. L.; Halas, N. J. Engineered Nanomaterials for Biophotonics Applications: Improving Sensing, Imaging, and Therapeutics. Annu. Rev. Biomed. Eng. 2003, 5, 285– 292. (24) Prodan, E.; Nordlander, P. Structural Tunability of the Plasmon Resonances in Metallic Nanoshells. Nano Lett. 2003, 3, 543–547. (25) Peglow, S.; Pohl, M.-M.; Kruth, A.; Brüser, V., Plasma Based Synthesis, Electron Microscopy, and Optical Characterization of Au-, Ag-, and Ag/Au-Core–Shell Nanoparticles. J. Phys. Chem. C 2014, 119, 563–572. 9 ACS Paragon Plus Environment


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 18

(26) Sun, Y.; Wiley, B.; Li, Z. –Y.; Xia, Y. Synthesis and Optical Properties of Nanorattles and Multiple-Walled Nanoshells/Nanotubes Made of Metal Alloys. J. Am. Chem. Soc. 2004, 126, 9399–9406. (27) Cho, E. C.; Camargo, P. H.; Xia, Y. Synthesis and Characterization of Noble‐Metal Nanostructures Containing Gold Nanorods in the Center. Adv. Mater. 2010, 22, 744–748. (28) Londono-Calderon, A.; Bahena, D.; Yacaman, M. J. Controlled Synthesis of Au@ AgAu Yolk–Shell Cuboctahedra with Well-Defined Facets. Langmuir 2016, 32, 7572– 7581. (29) Akbarzadeh, H.; Mehrjouei, E.; Shamkhali, A. N. Au@Void@Ag Yolk–Shell Nanoclusters Visited by Molecular Dynamics Simulation: The Effects of Structural Factors on Thermodynamic Stability. J. Phys. Chem. Lett. 2017, 8, 2990–2998. (30) Akbarzadeh, H.; Abbaspour, M.; Mehrjouei, E. Phase Transition in Crown-Jewel Structured Au–Ir Nanoalloys with Different Shapes: a Molecular Dynamics Study. Phys. Chem. Chem. Phys. 2016, 18, 25676–25686. (31) Yang, Y.; Zhao, Z.; Cui, R.; Wu, H.; Cheng, D. Structures, Thermal Stability, and Chemical Activity of Crown-Jewel-Structured Pd–Pt Nanoalloys. J. Phys. Chem. C 2014, 119, 10888–10895. (32) Fan, T. –E.; Liu, T. –D.; Zheng, J. –W.; Shao, G. –F.; Wen, Y. –H. Structure and Stability of Fe-Pt Bimetallic Nanoparticles: Initial Structure, Composition and Shape Effects. J. Alloys Compd. 2016, 685, 1008–1015. (33) Ali, S.; Myasnichenko, V.; Neyts, E. Size-Dependent Strain and Surface Energies of Gold Nanoclusters. Phys. Chem. Chem. Phys. 2016, 18, 792–800. (34) Bochicchio, D.; Ferrando, R. Morphological Instability of Core-Shell Metallic Nanoparticles. Phys. Rev. B 2013, 87, 165435. (35) Smith, W.; Todorov, I. T. A Short Description of DL_POLY. Mol. Simul. 2006, 32, 935–943. (36) Nosé, S. Constant-Temperature Molecular Dynamics. J. Phys.: Condens. Matter 1990, 2, SA115. (37) Hoover, W. G. Canonical Dynamics: Equilibrium Phase-Space Distributions. Phys. Rev. A 1985, 31, 1695.


Page 11 of 18

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(38) Allen, M. P.; Tildesley, D. J. Computer Simulation of Liquids; Oxford University Press: Clarendon, U. K.; 1997. (39) Çağin, Y. K. T.; Qi, Y.; Ikeda, H.; Johnson, W. L.; Goddard III, W. A. Calculation of Mechanical, Thermodynamic and Transport Properties of Metallic Glass Formers. Mater. Res. Soc. Symp. Proc. 1999, 554, 43–44. (40) Qi, Y.; Çağin, T.; Kimura, Y.; Goddard, W. A. Viscosities of Liquid Metal Alloys from Nonequilibrium Molecular Dynamics. J. Comput. Aided Mater. Des. 2001, 8, 233–243. (41) Li, M.; Cheng, D. Molecular Dynamics Simulation of the Melting Behavior of CrownJewel Structured Au–Pd Nanoalloys. J. Phys. Chem. C 2013, 117, 18746–18751. (42) Lykema, J.; Fleer, G.; Kleijn, J.; Leermakers, F.; Norde, W.; Van Vliet, T. Fundamentals of Interface and Colloid Science, volume III: Liquid-fluid interfaces; Academic Press: London, U. K.; 2000. (43) Akbarzadeh, H.; Abbaspour, M. Effect of Pressure on Some Properties of Ag@Pd and Pd@Ag Nanoclusters. J. Alloys Compd. 2017, 703, 174–179. (44) Wang, L.; Zhang, Y.; Bian, X.; Chen, Y. Melting of Cu Nanoclusters by Molecular Dynamics Simulation. Phys. Lett. A 2003, 310, 197–202. (45) Panizon, E.; Ferrando, R. Strain-Induced Restructuring of the Surface in Core@Shell Nanoalloys. Nanoscale 2016, 8, 15911–15919. (46) Ferrando, R. Symmetry Breaking and Morphological Instabilities in Core-Shell Metallic Nanoparticles. J. Phys.: Condens. Matter 2014, 27, 013003.



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Captions Figure caption: Figure 1. (a) Snapshots of atomic arrangement of Au@void@AgAu YSNPs with various morphologies (icosahedral (Ih), cuboctahedral (CO), decahedral (Dh), Marks-decahedral (m-Dh), and octahedral (Oh) at 1 and 300 K (b) Snapshots of cross sections of the mentioned YSNPs at 1 and 300 K. Coloring denotes type of atom: light green, Au atom and purple, Ag atom. Figure 2. ∆ parameters for Au@void@AgAu YSNPs as a function of morphology at 300 K. The corresponding snapshots of cross-sections of YSNPs at 300 K are presented as the insets. Figure 3. The surface energies for Au@void@AgAu YSNPs as a function of morphology at 300 K. The corresponding snapshots of cross-sections of YSNPs at 300 K are presented as the insets. Figure 4. Distribution of atomic strain for Au@void@AgAu YSNPs with various morphologies at 300 K. Atoms are ordered by increasing distance from center of the cluster. The vertical dashed line denotes the core-shell interface while the horizontal dashed line indicate the zero value. Figure 5. (a column) strain map of the surface of Au@void@AgAu YSNPs with various morphologies at 300 K and (b column) strain map of their cross-sections. Atoms are colored according to their local strain. The start value and end value in the color maps indicates minimum and maximum values of the strain.


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Figure 1:

(a)

(b)



Figure 2:

Structural stability parameter (eV)

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2.42

Ih

m-Dh

CO

Dh

Oh

Ih

m-Dh

CO

Dh

Oh

2.40 2.38 2.36 2.34 2.32 2.30 2.28 2.26 2.24 2.22

Morphology


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Figure 3:

0.000150

Surface energy (eV/Å2)

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Ih

m-Dh

CO

Dh

Oh

Ih

m-Dh

CO

Dh

Oh

0.000145

0.000140

0.000135

0.000130

0.000125

Morphology



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Figure 4:


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0.48

Ih

0.24 0.00 -0.24 0.93

m-Dh

0.62 0.31 0.00

Strain

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


-0.31 0.46

CO

0.23 0.00 -0.23 1.59

Dh

1.06 0.53 0.00 0.58

Oh

0.29 0.00 -0.29 -100

0

100

200

300

400

500

Atom i


600


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 5:


Page 18 of 18

Au@void@AgAu YolkâShell Nanoparticles with Dominant Strain

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