Crystallinity dynamics of gold nanoparticles during sintering or coalescence

Goudeli, Eirini; Pratsinis, Sotiris E.

doi:10.1002/aic.15125

Cited by 64 publications

(53 citation statements)

References 59 publications

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“…Once the particles are then in contact, a rapid surface driven coalescence find place within the first 300 ps (Figure f,g). The reduction of the surface energy drives the Au atoms from negative to positive curvature regions, forming a neck which increases in size leading to a reduction of the total surface area . The formed cluster assumes then a faceted triangular shape, which is stable up to the end of the simulation.…”

Section: Resultsmentioning

confidence: 99%

High‐Temperature Large‐Scale Self‐Assembly of Highly Faceted Monocrystalline Au Metasurfaces

Fusco

Rahmani

et al. 2018

Adv Funct Materials

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Localized surface plasmon resonance (LSPR) devices based on resonant metallic metasurfaces have shown disruptive potential for many applications including biosensing and photocatalysis. Despite significant progress, highly performing Au plasmonic nanotextures often suffer of suboptimal electric field enhancement, due to damping effects in multicrystalline domains. Fabricating well-defined Au nanocrystals over large surfaces is very challenging, and usually requires time-intensive multi-step processes. Here, presented are first insights on the large-scale self-assembly of monocrystalline Au nano-islands with tunable size and separation, and their application as efficient LSPR surfaces. Highly homogeneous centimeter-sized Au metasurfaces are fabricated by one-step deposition and in situ coalescence of hot nanoparticle aerosols into a discontinuous monolayer of highly faceted monocrystals. First insights on the mechanisms driving the high-temperature synthesis of these highly faceted Au nanotextures are obtained by molecular dynamic and detailed experimental investigation of their growth kinetics. Notably, these metasurfaces demonstrat high-quality and tunable LSPR, enabling the fabrication of highly performing optical gas molecule sensors detecting down to 3 × 10 −6 variations in refractive index at room temperature. It is believed that these findings provide a rapid, low-cost nanofabrication tool for the engineering of highly homogenous Au metasurfaces for large-scale LSPR devices with application ranging from ultrasensitive optical gas sensors to photocatalytic macroreactors.

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Section: Resultsmentioning

confidence: 99%

High‐Temperature Large‐Scale Self‐Assembly of Highly Faceted Monocrystalline Au Metasurfaces

Fusco

Rahmani

et al. 2018

Adv Funct Materials

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“…[67]. Understanding is rapidly advancing also at the sub-particle level, molecular or atomistic, with clever algorithms and hardware revealing detailed sintering or coalescence mechanisms [68] and even the dynamics of crystallinity development from first principles [69] on par with such efforts in soot dynamics [70]. In material synthesis this facilitates the development of process design correlations rigorously tested with data gradually placing flame aerosol technology on a firm scientific basis [26].…”

Section: Key Advances In Aerosol Science Enabling Materials Synthesismentioning

confidence: 99%

Flame synthesis of functional nanostructured materials and devices: Surface growth and aggregation

Kelesidis

Goudeli

Pratsinis

2017

Proceedings of the Combustion Institute

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143

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Combustion is essential to the manufacture of carbon black, fumed oxides, optical fibers and, recently, new high-value products like carbon nanotubes, nanosilver and biomagnetic nanofluids that are driven to market predominantly by startups. This technology is attractive for material synthesis for its proven scalability as it does not involve the tedious steps of wet chemistry and can readily form stably metastable compositions and high purity products. Recent advances in aerosol and combustion sciences reveal that coagulation and sintering and/or surface growth control product particle size and morphology through the high temperature particle residence time, self-preserving size distribution and power laws for fractal-like particles. This motivates synthesis of an array of unique particle compositions and morphologies primarily by spray combustion leading to new catalysts, gas sensors and bio-materials and, most recently, to hand-held devices such as breath analysis sensors for monitoring chronic illnesses. In particular, multi-scale process design integrating mesoscale and molecular dynamics facilitates understanding of combustion product development. The latter contributes also to understanding of aggregation and surface growth of nascent soot, a bona fide nanostructured material! So here nascent soot dynamics, after nucleation or inception, are investigated through accounting of soot agglomeration and surface growth by acetylene pyrolysis. Neglecting the fractal-like nature of soot underestimates its mobility diameter and polydispersity up to 40%. The evolution of nascent soot structure from spheres to aggregates is quantified by the mass fractal dimension and mass-mobility exponent, in excellent agreement with microscopic and mass-mobility measurements in a standard burner-stabilized stagnation ethylene flame. Surface growth chemically bonds the constituent primary particles of these aggregates, while the effect of soot volume fraction on soot morphology is elucidated. Based on aggregate projected area, a scaling law is derived for determining the primary particle size of nascent soot aggregates from mass-mobility measurements rather than tedious image counting.

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“…Sintering of gold catalysts is one of the main issues with their large‐scale application, because of the low melting point of Au, especially at the nanoscale . Colloidally synthesized NCs with a narrow size distribution provide a convenient way to study NC sintering using post‐catalysis TEM analysis because of their very narrow particle size distributions and well‐defined shape.…”

Section: Resultsmentioning

confidence: 99%

Understanding the preferential oxidation of carbon monoxide (PrOx) using size‐controlled Au nanocrystal catalyst

et al. 2018

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Removing CO from hydrogen streams is an important industrial process. The catalytic preferential oxidation of CO (PrOx) is a promising method for CO removal, leaving the hydrogen concentration unchanged. Here, the effect of size and support on the gold-catalyzed PrOx reaction using size-controlled Au nanocrystals (NCs) is investigated. For all supports, Au NC sizes of 2-5 nm show the highest rates, whereas for larger sizes rates drop. Ceria-supported Au shows by far the best performance. By analyzing the dependency of the reaction rate on the NC diameter, the most active centers for CO oxidation on Au/CeO 2 are Au 1 corner atoms at the interface with the support, resulting in 2.1 nm Au NCs supported on ceria reaching full O 2 conversion and CO selectivity of about 50%. Therefore, it is suggested that increasing the fraction of Au-ceria interface sites would lead to the best performing materials for this reaction.

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Crystallinity dynamics of gold nanoparticles during sintering or coalescence

Cited by 64 publications

References 59 publications

High‐Temperature Large‐Scale Self‐Assembly of Highly Faceted Monocrystalline Au Metasurfaces

High‐Temperature Large‐Scale Self‐Assembly of Highly Faceted Monocrystalline Au Metasurfaces

Flame synthesis of functional nanostructured materials and devices: Surface growth and aggregation

Understanding the preferential oxidation of carbon monoxide (PrOx) using size‐controlled Au nanocrystal catalyst

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