3D characterization of heat-induced morphological changes of Au nanostars by fast <i>in situ</i> electron tomography

Vanrompay, Hans; Bladt, Eva; Albrecht, Wiebke; Béché, Armand; Zakhozheva, Marina; Sánchez‐Iglesias, Ana; Liz‐Marzán, Luis M.; Bals, Sara

doi:10.1039/c8nr08376b

Cited by 67 publications

(132 citation statements)

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“…Other indirect evidence of alloy formation is provided by 2D energy‐dispersive X‐ray (EDX) projection images. However, 2D TEM projection images of 3D objects can be very misleading and are not necessarily representative for the real 3D composition …”

Section: Introductionmentioning

confidence: 99%

Unraveling Structural Information of Turkevich Synthesized Plasmonic Gold–Silver Bimetallic Nanoparticles

Blommaerts

Vanrompay

Nuti

et al. 2019

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nanoelectronic devices. [21,23] Bimetallic nanoparticles are of specific interest because of their versatility and tunability mainly for (photo)catalytic applications. Especially the gold-silver combination has been thoroughly investigated due to its optical surface plasmon resonance (SPR) absorbance that can be tuned over the entire visible range of the electromagnetic spectrum, merely depending on the composition of both metals. [2,13,14,24] Various methods have been applied to synthesize Au-Ag bimetallic nanoparticles, of which the most widely used is the Turkevich method. [25] This method is based on the coreduction of metal precursors in the presence of a stabilizing agent, usually sodium citrate, in boiling water. Most studies report on the formation of alloy nanoparticles, [26][27][28][29][30][31][32] although some researchers have also indicated the possible formation of core-shell structures. [29,33] The assumption of a full alloy composition is mostly based on UV-vis absorption data, that only show one single plasmon band in the visible light range. [29][30][31][32]34,35] Indeed, two separate plasmon bands are usually observed in the case of a core-shell structure. [27,35,36] Hereby, it is important to note that according to Mie theory, the total extinction cross-section scales with the volume of the nanoparticles. [37] The observation of only one plasmon band in the UV-vis spectrum therefore not excludes a core-shell structure, since such a morphology with a sufficiently thick shell also leads to a sole plasmon band. Other indirect evidence of alloy formation is provided by 2D energy-dispersive X-ray (EDX) projection images. However, 2D TEM projection images of 3D objects can be very misleading and are not necessarily representative for the real 3D composition. [38] In this work, we aim to accurately elucidate the real structure and synthesis pathway of gold-silver bimetallic nanoparticles, synthesized according to the universally applied Turkevich method, by analyzing samples taken at several time intervals during the synthesis. An experimental wet-chemical study is linked to both an advanced electron microscopy analysis, including EDX tomography, and extensive modeling. In this way a complete analysis is provided to once and for all unravel the structural enigma surrounding the Turkevich synthesis of gold-silver bimetallic nanoparticles.For the synthesis of gold-silver bimetallic nanoparticles, the Turkevich method has been the state-of-the-art method for several decades. It is presumed that this procedure results in a homogeneous alloy, although this has been debatable for many years. In this work, it is shown that neither a full alloy, nor a perfect core-shell particle is formed but rather a core-shelllike particle with altering metal composition along the radial direction. In-depth wet-chemical experiments are performed in combination with advanced transmission electron microscopy, including energy-dispersive X-ray tomography, and finite element method modeling to support the observations. From th...

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Section: Introductionmentioning

confidence: 99%

Unraveling Structural Information of Turkevich Synthesized Plasmonic Gold–Silver Bimetallic Nanoparticles

Blommaerts

Vanrompay

Nuti

et al. 2019

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“…This result is similar to recent studies based on photothermal reshaping, 36 where it is shown that anisotropic particles evolve towards a spherical morphology due to the higher mobility and lower melting point of atoms at corners or tips. 37 Several aliquots were extracted at different times during the heating process and cooled down to quench reshaping. Each aliquot was further partitioned into three equal volumes and MBA, ABT, or 4-acetylaminobenzenthiol (AABT) were then added.…”

Section: Resultsmentioning

confidence: 99%

Manipulating chemistry through nanoparticle morphology

et al. 2020

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“…[14][15][16] Alternatively, electron tomography (ET) techniques enable researchers to reconstruct three-dimensional images of nanoparticles using two-dimensional projection TEM/ STEM images and eventually determine the functionality of many structures. [17][18][19][20][21][22] Currently, following the developments of electron sources, spectrometers and spherical-aberration correctors, applications of electron microscopy in semiconductors, materials science, and biological science are booming. [23][24][25][26] Moreover, the newly invented direct electron detection camera makes it possible to work with both high spatial and temporal resolution at the same time, laying a solid foundation to record the structural evolution of nanoparticles in response to mechanical, thermal, and/or chemical stimulations.…”

Section: Introductionmentioning

confidence: 99%

In‐situ Transmission Electron Microscope Techniques for Heterogeneous Catalysis

Zhang

Liu

et al. 2020

ChemCatChem

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The physicochemical properties of heterogeneous catalysts in static or inert environments often deviate greatly from the properties under in‐situ or working conditions. To gain an insightful understanding of realistic catalyst properties and the corresponding catalytic mechanisms, it is essential to identify and rationalize changes in catalysts under reaction conditions. In recent years, in‐situ transmission electron microscope (in‐situ TEM) techniques have been increasingly developed, offering a unique approach to visualize the evolution of heterogeneous catalysis with ultra‐high spatial resolution, good energy resolution and reasonable temporal resolution under controllable or even realistic catalytic conditions. In this review, we have summarized recent advances in the in‐situ TEM analysis of heterogeneous catalysis, which suggests the great potential of this technique in this important field. Furthermore, technical challenges and possible solutions are discussed.

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3D characterization of heat-induced morphological changes of Au nanostars by fast in situ electron tomography

Abstract: The thermal reshaping and its influence on the plasmonic properties of gold nanostars are investigated using a combination of in situ tomography and a state-of-the-art fast acquisition approach.

Cited by 67 publications

References 40 publications

Unraveling Structural Information of Turkevich Synthesized Plasmonic Gold–Silver Bimetallic Nanoparticles

Unraveling Structural Information of Turkevich Synthesized Plasmonic Gold–Silver Bimetallic Nanoparticles

Manipulating chemistry through nanoparticle morphology

In‐situ Transmission Electron Microscope Techniques for Heterogeneous Catalysis

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