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Hamid SBA, Schlögl R. The Impact of Nanoscience in Heterogeneous Catalysis. THE NANO‐MICRO INTERFACE 2015:405-430. [DOI: 10.1002/9783527679195.ch20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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2
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Mayence A, Wang D, Salazar-Alvarez G, Oleynikov P, Bergström L. Probing planar defects in nanoparticle superlattices by 3D small-angle electron diffraction tomography and real space imaging. NANOSCALE 2014; 6:13803-8. [PMID: 25292411 DOI: 10.1039/c4nr04156a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We demonstrate how the acquisition and processing of 3D electron diffraction data can be extended to characterize structural features on the mesoscale, and show how lattice distortions in superlattices of self-assembled spherical Pd nanoparticles can be quantified by three-dimensional small-angle electron diffraction tomography (3D SA-EDT). Transmission electron microscopy real space imaging and 3D SA-EDT reveal a high density of stacking faults that was related to a competition between fcc and hcp arrangements during assembly. Information on the orientation of the stacking faults was used to make analogies between planar defects in the superlattices and Shockley partial dislocations in metallic systems.
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Affiliation(s)
- Arnaud Mayence
- Arrhenius Laboratory, Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, Sweden.
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3
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Stappert S, Rellinghaus B, Acet M, Wassermann EF. Multiply Twinned Structures in Gas-Phase Sintered Stoichiometric FePt Nanoparticles. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-704-w5.7.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractStoichiometric FePt nanoparticles with sizes in the range 3 – 6 nm were prepared in the gas-phase and thermally sintered prior to deposition. Whereas unsintered particles exhibit irregular shapes and a low degree of crystallinity, the majority of the sintered particles are multiply twinned and have predominantly icosahedral structure. There is no indication for the occurance of L10 ordering in the gas-phase sintered particles, although previous post-deposition annealing experiments of unsintered particles had shown the occurrence of partial formation of the L10 FePt intermetallic phase. On the other hand, analysis of the structural data obtained from (high resolution) electron microscopy shows that the relative amount of icosahedral particles increases with increasing sintering temperature. This result is discussed on the basis of a structure model of an irregular icosahedron, which is built up from distorted tetrahedral building blocks. The distortion in each tetrahedron is in accordance with the tetragonally compressed unit cell of the L10-phase.
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4
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Goubet N, Pileni MP. Crystal growth from cluster to bulk materials via nanomaterials. Z KRIST-CRYST MATER 2009. [DOI: 10.1524/zkri.2007.222.11.663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In this short paper we propose the hypothesis that, in highly pure media, the cluster shape can be retained at various scales. Impurities and/or the additives can control the shape of the developing crystals by adsorption on selective sites.
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Pelka J, Gehrke H, Esselen M, Türk M, Crone M, Bräse S, Muller T, Blank H, Send W, Zibat V, Brenner P, Schneider R, Gerthsen D, Marko D. Cellular uptake of platinum nanoparticles in human colon carcinoma cells and their impact on cellular redox systems and DNA integrity. Chem Res Toxicol 2009; 22:649-59. [PMID: 19290672 DOI: 10.1021/tx800354g] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Supercritical fluid reactive deposition was used for the deposition of highly dispersed platinum nanoparticles with controllable metal content and particle size distribution on beta-cyclodextrin. The average particle size and size distribution were steered by the precursor reduction conditions, resulting in particle preparations <20, <100, and >100 nm as characterized by transmission electron microscopy and scanning electron microscopy (SEM). These particle preparations of different size distributions were used to address the question as to whether metallic platinum particles are able to invade cells of the gastrointestinal tract as exemplified for the human colon carcinoma cell line HT29 and thus affect the cellular redox status and DNA integrity. Combined focused ion beam and SEM demonstrated that platinum nanoparticles were taken up into HT29 cells in their particulate form. The chemical composition of the particles within the cells was confirmed by energy-dispersive X-ray spectroscopy. The potential influence of platinum nanoparticles on cellular redoxsystems was determined in the DCF assay, on the translocation of Nrf-2 and by monitoring the intracellular glutathione (GSH) levels. The impact on DNA integrity was investigated by single cell gel electrophoresis (comet assay) including the formation of sites sensitive to formamidopyrimidine-DNA-glycosylase. Platinum nanoparticles were found to decrease the cellular GSH level and to impair DNA integrity with a maximal effect at 1 ng/cm(2). These effects were correlated with the particle size in an inverse manner and were enhanced with increasing incubation time but appeared not to be based on the formation of reactive oxygen species.
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Affiliation(s)
- Joanna Pelka
- Institut für Angewandte Biowissenschaften, Abteilung für Lebensmitteltoxikologie, Universitt Karlsruhe (TH), Karlsruhe, Germany
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6
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Probing atomic ordering and multiple twinning in metal nanocrystals through their vibrations. Proc Natl Acad Sci U S A 2008; 105:14784-9. [PMID: 18818308 DOI: 10.1073/pnas.0803748105] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Control of nanocrystal (NC) crystallinity currently raises great interest because of its potential benefits in both physics modeling and technological applications. Advances in methods for synthesizing perfect single-crystalline NCs are recent, so that the effect of crystallinity on NC properties has received only limited study and still needs to be properly investigated. Here, we report that crystallinity of gold NCs dramatically modifies their vibrations. Using low-frequency Raman scattering, we clearly demonstrate that single-domain NCs vibrate differently than their multiply twinned counterparts, through the splitting of the quadrupolar vibrations, which is only observed for the former. Using the resonant ultrasound approach, we calculate the vibrational frequencies of a gold sphere and show that elastic anisotropy induces a lift of degeneracy of the quadrupolar mode in good agreement with our experimental measurements. These findings open up challenging perspectives on using Raman spectroscopy to characterize nanocrystallinity.
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Ni C, Hassan PA, Kaler EW. Structural characteristics and growth of pentagonal silver nanorods prepared by a surfactant method. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:3334-3337. [PMID: 15807571 DOI: 10.1021/la046807c] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The crystal structure and growth mechanism of silver nanorods prepared by a seed-mediated surfactant method using the cationic surfactant cetyltrimethylammonium tosylate (CTAT) and its wormlike micelles are characterized by conventional and high-resolution transmission electron microscopy. Depending on the nanorod orientations, two types of electron diffraction patterns are obtained from a truncated decahedral structure consisting of five crystal units packing along [111] twining planes with five [111] planes on each end and five circumferential [001] side surfaces parallel to a <110> longitudinal direction. High-resolution images of the nanorods and the corresponding Fourier transform patterns confirm the results from the morphological and diffraction analyses. The silver nanorods grow only from multiply twinned decahedral seeds, and the high selectivity of surfactant attachment results in a barrier to the transfer of silver atoms from the solution to the circumferential [100] planes. Blockage of circumferential growth causes the aspect ratio of the rod to grow.
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Affiliation(s)
- Chaoying Ni
- Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, USA.
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Wanner M, Gerthsen D, Jester SS, Sarkar B, Schwederski B. Treatment of citrate-capped Au colloids with NaCl, NaBr and Na2SO4: a TEM, EAS and EPR study of the accompanying changes. Colloid Polym Sci 2005. [DOI: 10.1007/s00396-004-1226-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Salzemann C, Lisiecki I, Urban J, Pileni MP. Anisotropic copper nanocrystals synthesized in a supersaturated medium: nanocrystal growth. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:11772-11777. [PMID: 15595810 DOI: 10.1021/la0492862] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In the chemical reduction of copper ions in mixed reverse micelles it is found that a large excess of reducing agent favors the production of a new generation of copper nanocrystals. At low reducing agent concentration, nanocrystals are mostly spherical, while in the supersaturated regime, they have various shapes such as pentagons, squares, triangles, and elongated forms. The nanocrystal structures, characterized by high-resolution transmission electron microscopy, are based on the face-centered cubic structure. A tentative explanation for the growth mechanism of copper nanocrystals having various shapes is proposed.
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Affiliation(s)
- C Salzemann
- Fritz-Haber-Institut der MPG, Abt. AC, 4-6 Faradayweg, D-14195 Berlin, Germany
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González JC, Rodrigues V, Bettini J, Rego LGC, Rocha AR, Coura PZ, Dantas SO, Sato F, Galvão DS, Ugarte D. Indication of unusual pentagonal structures in atomic-size Cu nanowires. PHYSICAL REVIEW LETTERS 2004; 93:126103. [PMID: 15447283 DOI: 10.1103/physrevlett.93.126103] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Indexed: 05/24/2023]
Abstract
We present a study of the structural and quantum conductance properties of atomic-size copper nanowires generated by mechanical stretching. The atomistic evolution was derived from time-resolved electron microscopy observations and molecular dynamics simulations. We have analyzed the quantum transport behavior by means of conductance measurements and theoretical calculations. The results suggest the formation of an unusual and highly stable pentagonal Cu nanowire with a diameter of approximately 0.45 nm and approximately 4.5 conductance quanta.
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Affiliation(s)
- J C González
- Laboratório Nacional de Luz Síncrotron, C.P. 6192, 13084-971 Campinas, São Paulo, Brazil
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Salzemann C, Lisiecki I, Brioude A, Urban J, Pileni MP. Collections of Copper Nanocrystals Characterized by Different Sizes and Shapes: Optical Response of These Nanoobjects. J Phys Chem B 2004. [DOI: 10.1021/jp048491n] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. Salzemann
- Fritz-Haber-Institut der MPG, Abteilung AC, 4-6 Faradayweg, D-14195 Berlin, Germany, and Laboratoire L.M.2.N., U.M.R. C.N.R.S. 7070 Université Pierre et Marie Curie (Paris VI), B.P. 52, 4 place Jussieu, F-752 31 Paris Cedex 05, France
| | - I. Lisiecki
- Fritz-Haber-Institut der MPG, Abteilung AC, 4-6 Faradayweg, D-14195 Berlin, Germany, and Laboratoire L.M.2.N., U.M.R. C.N.R.S. 7070 Université Pierre et Marie Curie (Paris VI), B.P. 52, 4 place Jussieu, F-752 31 Paris Cedex 05, France
| | - A. Brioude
- Fritz-Haber-Institut der MPG, Abteilung AC, 4-6 Faradayweg, D-14195 Berlin, Germany, and Laboratoire L.M.2.N., U.M.R. C.N.R.S. 7070 Université Pierre et Marie Curie (Paris VI), B.P. 52, 4 place Jussieu, F-752 31 Paris Cedex 05, France
| | - J. Urban
- Fritz-Haber-Institut der MPG, Abteilung AC, 4-6 Faradayweg, D-14195 Berlin, Germany, and Laboratoire L.M.2.N., U.M.R. C.N.R.S. 7070 Université Pierre et Marie Curie (Paris VI), B.P. 52, 4 place Jussieu, F-752 31 Paris Cedex 05, France
| | - M.-P. Pileni
- Fritz-Haber-Institut der MPG, Abteilung AC, 4-6 Faradayweg, D-14195 Berlin, Germany, and Laboratoire L.M.2.N., U.M.R. C.N.R.S. 7070 Université Pierre et Marie Curie (Paris VI), B.P. 52, 4 place Jussieu, F-752 31 Paris Cedex 05, France
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Chen H, Gao Y, Zhang H, Liu L, Yu H, Tian H, Xie S, Li J. Transmission-Electron-Microscopy Study on Fivefold Twinned Silver Nanorods. J Phys Chem B 2004. [DOI: 10.1021/jp048023d] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hanyuan Chen
- Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Yan Gao
- Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Huairou Zhang
- Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Libao Liu
- Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Hongchun Yu
- Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Huanfang Tian
- Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Sishen Xie
- Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
| | - Jianqi Li
- Beijing Laboratory of Electron Microscopy, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
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Tsen SCY, Crozier PA, Liu J. Lattice measurement and alloy compositions in metal and bimetallic nanoparticles. Ultramicroscopy 2003; 98:63-72. [PMID: 14609644 DOI: 10.1016/s0304-3991(03)00119-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A new reliable method for determining the lattice spacings of metallic and bimetallic nanoparticles in phase contrast high resolution electron microscopy (HREM) images was developed. In this study, we discuss problems in applying HREM techniques to single metal (Pt and Au) and bimetallic (AuPd) nanoparticles of unknown shapes and random orientations. Errors arising from particle tilt and edge effects are discussed and analysis criteria are presented to reduce these errors in measuring the lattice parameters of nanoparticles. The accuracy of an individual particle lattice measurement is limited by an effective standard deviation which depends on the size of the individual nanoparticle. For example, the standard deviation for 20-30 A Pt or Au nanoparticles is about 1.5%. To increase the accuracy in determining the lattice spacings of nanoparticles, statistical methods have to be used to obtain the average lattice spacing of an ensemble of nanoparticles. We measured approximately 100 nanoparticles with sizes in the range of 20-30 A and found that the mean lattice spacing can be determined to within 0.2%. By applying Vegard's law to the AuPd bimetallic systems we successfully detected the presence of alloying. For 30 A nanoparticles, the estimated ultimate error in determining the composition of the AuPd alloy is about 3% provided that at least 100 particles are measured. Finally, the challenges in determining the presence of more than one alloy phases in bimetallic nanoparticle systems were also discussed.
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Affiliation(s)
- S-C Y Tsen
- Department of Physics, Arizona State University, PO Box 871704, Tempe, AZ 85287-1704, USA
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The jig-saw puzzle of crystal structures: Alloys, superconducting oxides, semiconductors, ionic conductors, surface adsorbates and magnetic structures. PROG SOLID STATE CH 2000. [DOI: 10.1016/s0079-6786(00)00005-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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