Size-tunable uniform gold octahedra: fast synthesis, characterization, and plasmonic properties

Lu, Yuehui; Zhang, Haibin; Wu, Fan; Liu, Hong; Fang, Jingzhong

doi:10.1039/c7ra01223c

Cited by 27 publications

(24 citation statements)

References 37 publications

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“…In the high CO chemical potential area (Δμ CO > −0.8 eV), the Wulff shape of FCC Co becomes an octahedron occupied by nearly all {111} surfaces. This kind of shape is usually synthesized by hydrothermal experiments through certain kinds of surface ligands used in Au, Ag, and Co nanocatalysts by tuning their surface energies. − Our theoretical predictions are consistent with the previous theoretical report that the most exposed surface of FCC Co is always {111} regardless of the CO chemical potential. However, the {311} surface can present in FCC Co shape in our work when the CO chemical potential is below −1.2 eV, which is different from Hou’s report .…”

Section: Resultssupporting

confidence: 88%

Morphology Evolution of FCC and HCP Cobalt Induced by a CO Atmosphere from Ab Initio Thermodynamics

et al. 2020

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Fischer−Tropsch synthesis, the conversion of CO and H 2 to long-chain hydrocarbons, is performed at relatively low temperatures and high pressures over the most commonly encountered iron-, ruthenium-, or cobalt-based catalysts. Identification of the morphologies and structure evolution of FTS catalysts under reaction conditions are essential for understanding the structure−reactivity relationship. In this work, we performed a comprehensive ab initio thermodynamics study to provide an understanding of the morphology evolution of cobalt (Co) catalyst with hexagonal close-packed (HCP) and face-centered cubic (FCC) crystal structures under a CO atmosphere. CO adsorption on numerous surfaces of HCP Co and FCC Co at different coverages were investigated. On both HCP Co and FCC Co, lateral interaction is attractive at lower coverage and becomes repulsive at higher coverage. Compared to FCC Co, though in average CO adsorption on HCP Co is stronger at lower coverage, they become similar at higher coverage due to the overwhelming lateral repulsion. We established the phase diagrams and the morphology evolution of FCC Co and HCP Co as a function of CO chemical potentials. The most probable exposed facets in FCC Co and HCP Co Wulff shapes were revealed under different CO atmospheres. At a relatively low CO chemical potential, many open facets could be exposed in Co equilibrium morphology, including {101̅ 2}, {101̅ 1}, {101̅ 0}, and {112̅ 0} facets for HCP Co and {311}, {110}, and {100} facets for FCC Co. In contrast, at a relatively high CO chemical potential, FCC Co has an octahedron shape composed entirely by close-packed {111} facets, while HCP Co is hexagonal prism shaped composed mainly by close-packed {0001} and {101̅ 0} facets. The morphology evolution of HCP and FCC phases would have great impact on the inherited catalytic performance of Co nanoparticles, thus will selectively regulate their chemical reactivity.

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Section: Resultssupporting

confidence: 88%

Morphology Evolution of FCC and HCP Cobalt Induced by a CO Atmosphere from Ab Initio Thermodynamics

et al. 2020

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“…The octahedral gold nanoparticles were synthesised using published protocols [37,38] with poly(diallyldimethylammonium) chloride (PDDA) polymer coating to avoid aggregation. The cubic particles were synthesized in water using the method described in Park et al [39] with cetyltrimethylammonium chloride (CTAC) as a stabilising agent.…”

Section: Sample Preparationmentioning

confidence: 99%

3D diffractive imaging of nanoparticle ensembles using an x-ray laser

Ayyer

Xavier

Bielecki

et al. 2020

Optica

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We report the 3D structure determination of gold nanoparticles (AuNPs) by X-ray single particle imaging (SPI). Around 10 million diffraction patterns from gold nanoparticles were measured in less than 100 hours of beam time, more than 100 times the amount of data in any single prior SPI experiment, using the new capabilities of the European X-ray free electron laser which allow measurements of 1500 frames per second. A classification and structural sorting method was developed to disentangle the heterogeneity of the particles and to obtain a resolution of better than 3 nm. With these new experimental and analytical developments, we have entered a new era for the SPI method and the path towards close-to-atomic resolution imaging of biomolecules is apparent.

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“…Due to the fact that the LSPR effect of noble metal nanoparticles is closely related to their morphology and size, a lot of research has been devoted to regulating the morphology and size of noble metal nanoparticles in the past few decades. Many noble metal nanoparticles with regular morphology and uniform size, including spherical [6,7], octahedral [8,9], cubic [10,11], rhombic [12,13], rod-shaped [14,15], plate-shaped [16,17], and high-index facet nanoparticles [18][19][20], have been prepared. In addition, in the application field of SERS, noble metal nanoparticles with sharp tips or porous structure usually show more excellent effects.…”

Section: Introductionmentioning

confidence: 99%

Facile Synthesis of Porous Ag Crystals as SERS Sensor for Detection of Five Methamphetamine Analogs

Qin

Yao

et al. 2022

Molecules

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Porous noble metal nanomaterials have attracted extensive attention due to their high specific surface area and surface plasmon resonance effect. However, it is difficult to form porous structures due to the high mobility and low reduction potential of noble metal precursors. In this article, we developed a facile method for preparing porous Ag with a controllable structure at room temperature. Two kinds of Ag crystals with different porous structures were successfully prepared by using AgCl cubes as sacrificial templates. Through the galvanic replacement reaction of Zn and AgCl, Ag crystals with a sponge-like porous structure were successfully prepared. Additionally, using NaBH4 as the reducing agent, we prepared granular porous Ag cubes by optimizing the amount of reducing agent. Both the sponge-like and granular porous Ag cubes have clean and accessible surfaces. In addition, we used the prepared two porous Ag cubes as substrate materials for SERS detection of five kinds of methamphetamine analogs. The experimental results show that the enhancement effect of granular porous Ag is better than that of sponge-like porous Ag. Furthermore, we probed the hot spot distribution of granular porous Ag by Raman mapping. By using granular porous Ag as the substrate material, we have achieved trace detection of 5 kinds of methamphetamine analogs including Ephedrine, Amphetamine, N-Methyl-1-(benzofuran-5-yl)propan-2-amine (5-MAPB), N-Methyl-1-(4-methoxyphenyl)propan-2-amine (PMMA) and N-Methyl-1-(4-fluorophenyl)propan-2-amine (4-FMA). Furthermore, to achieve qualitative differentiation of analogs with similar structures we performed density functional theoretical (DFT) calculations on the Raman spectra of the above analogs. The DFT calculations provided the vibrational frequencies, Raman activities, and normal mode assignment for each analog, enabling the qualitative differentiation of the above analogs.

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Size-tunable uniform gold octahedra: fast synthesis, characterization, and plasmonic properties

Abstract: Well-defined octahedral Au nanocrystals were facilely and precisely prepared in high yield by modified polyol process.

Cited by 27 publications

References 37 publications

Morphology Evolution of FCC and HCP Cobalt Induced by a CO Atmosphere from Ab Initio Thermodynamics

Morphology Evolution of FCC and HCP Cobalt Induced by a CO Atmosphere from Ab Initio Thermodynamics

3D diffractive imaging of nanoparticle ensembles using an x-ray laser

Facile Synthesis of Porous Ag Crystals as SERS Sensor for Detection of Five Methamphetamine Analogs

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