Facile synthesis of SiO2–Au nanoshells in a three-stage microfluidic system

Gómez, Leyre; Arruebo, Manuel; Sebastián, Víctor; Gutierrez, Laura Beatriz; Santamarı́a, Jesús

doi:10.1039/c2jm34206e

Cited by 53 publications

(44 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In the last years, there has been an intense activity in the application of this technology to the synthesis of high quality nanomaterials . Nanocrystalline colloids of a wide variety of nanomaterials have been synthesized, including simple nanostructures such as Cu, Au, CdS, TiO 2 , SiO 2 , MOFs, and complex nanostructures with a core‐shell morphology such as SiO 2 /Au, CdSe/ZnSe/ZnS, or even hollow nanostructures . However, the production of nanostructures under a shape control process in which kinetic control prevails over thermodynamic factors, is practically unexplored because of the great number of variables affecting the growth process of anisotropic nanocrystals (kinetics, synthesis conditions, ligands, additives) .…”

Section: Introductionmentioning

confidence: 99%

Continuous synthesis of palladium nanorods in oxidative segmented flow

2015

Self Cite

View full text Add to dashboard Cite

in Wiley Online Library (wileyonlinelibrary.com)Laminar and segmented flow methods are presented for producing Pd rod-shaped nanostructures from Na 2 PdCl 4 in mixtures of water, ethylene glycol, polyvinyl pyrrolidone, and KBr. Synthesis in laminar flow produced an evolution from Pd nanoparticles to short nanorods with residence time. Use of air as the segmentation gas tuned the oxidative environment promoting anisotropic growth of Pd. Moreover, the elevated temperatures (1608C and 1908C) and pressure (0.8 MPa) reduced the synthesis time from hours for most batch systems to 2 min. The ratio of polyol and Pd precursor metal flow streams controlled the anisotropic growth, obtaining nanorods with a diameter approximately 4 nm and an aspect ratio up to 6. Nanorods were single crystal with the {100} lattice spacing of fcc structure, and without any dislocation, stacking fault, or twin defects. The resulting Pd nanorods had high activity at moderate temperature (40 C) and pressure (0.2 MPa) in the catalytic hydrogenation of styrene.

show abstract

Section: Introductionmentioning

confidence: 99%

Continuous synthesis of palladium nanorods in oxidative segmented flow

2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Moreover, diffusive mixing and mass transfer are enhanced due to the small dimension. Importantly, manipulation of the reagents concentrations in both space and time provides an additional level of reaction control that is not attainable in bulk stirred reactors 46,47 .Continuous synthesis of SGNU was performed in a flow microreactor made of PTFE tubes and fed by syringe pumps ( Fig. 1b and Fig.…”

mentioning

confidence: 99%

Engineering the synthesis of silica–gold nano-urchin particles using continuous synthesis

2014

View full text Add to dashboard Cite

Compared to freestanding nanoparticles, supported nanostructures typically show better mechanical stability as well as ease of handling. Unique shapes such as core-shells, raspberries and crescents have been developed on supported materials to gain improved chemical and optical properties along with versatility and tunability. We report the formation of hyperbranched gold structures on silica particles, silica-gold nano-urchin (SGNU) particles. Kinetic control of crystallization, fast mass transfer as well as a bumped surface morphology of the silica particles are important factors for the growth of gold branches on the silica support. Using a microfluidic platform, continuous synthesis of SGNUs is achieved with increased reaction rate (less than 12 min. of residence time), better controllability and reproducibility than that obtained in batch synthesis. The hyper-branched gold structures display surfaceenhanced Raman scattering (SERS). Introduction.Microfluidic systems offer excellent conditions for synthesis of nanomaterials by control of mixing, temperature, and pressure combined with fast heat and mass transfer. 1, 2 Moreover, they enable controlled synthesis under higher temperature and pressure conditions than typically feasible in batch with resulting faster synthesis. 1, 3 Herein, we report batch and microfluidic synthesis of hyper-branched gold structures on silica particles, silica-gold nano-urchin (SGNU) particles. The formed particles consist of a dielectric silica core decorated with densely packed gold nanobranches stretching outward. The morphology serves as an active substrate for tip-enhanced Raman scattering, 4 and could additional have applications in catalysis and bio-imaging. 5,6 Gold nanoparticles have been synthesized by a variety of approaches for diverse applications in catalysis, bio-imaging, drug delivery and photovoltaics. Their surface plasmon resonance (SPR) and surface enhanced Raman scattering (SERS) properties have been of particular interest for photothermal therapy and molecular sensing, respectively [7][8][9][10][11][12][13][14][15] . SERS active structures have been fabricated by complex with top-down methods, 4,12,16,17 but wet-chemical synthesis of gold nanoparticles offer potential advantages in simple, high yield, and limited scalable synthesis. 12,18,19,20,21,22 Gold nanostructures, such as nanorods, nanowires, tetrapods, nanoplates and star-shaped particles are particularly attractive for many applications because of their strong confinement of the electromagnetic field and high enhancement that can be tuned over a wide range of optical wave lengths in comparison with ordinary spherical structures. 11,[23][24][25][26][27] Combination of the metal nanostructure with a support material, such as in core-shells, raspberries, and crescents, affords additional advantages in tuning optical properties, improved chemical/mechanical stability, and ease of handling compared to free-standing nanoparticles.Batch methods, 20 specialized ligands 28 and additional electrochemical treat...

show abstract

“…1c includes the optical spectrum of PS@Au Nano shell which have peak about 400-500nm that return to the thick of Au shell around PS core that's appear in Fig.2 . For fig1b shows the UV-Vis absorption spectra of the PS/Au-Cu composites fabricated using different concentration of the CuSO 4 .5H 2 O molar solution, where a clear plasmon is observed of Nano shells that's similar to [12] . The position and width of the SPR peak are linked with the size and shape of the metal particles, also connected with its own dielectric constant and that around it.…”

Section: Results and Discussion -3mentioning

confidence: 99%

Preparation and Optical Properties of PS @Au-Cu Core-Shell Nano Composite

Rudainah

Farkad²,

2015

ILCPA

View full text Add to dashboard Cite

An appropriate low-cost uncomplicated chemical method has been used to obtain the optical properties in the production of plasmon by manufacturing nanomaterial's consisting of dielectric core and a shell that grows on its surface . This core consists of the polystyrene PS and a goldcopper shell. The synthesis was made in two steps . In the first step PS core was fabricated , then coated by a shell consisting of Au -Cu particles . The shell shape differs according to the change in the amount of molar concentrations of Cu, and H2O2. It is found that variation of this materials amount gives us absorbance measurements (Localised Surface Plasmon Resonance, LSPR) that increase proportionally with changing quantities directly, where the size of core is constant .And the peak position in blue shift high energy then changes to red shift low energy . This change depends on the size and shape of particles. The same case applies for the transmittance of its change with the change of this material. The nano shell was characterized by using Scanning electron microscopy,SEM and UV -vis spectroscopy by varying the amount of Cu and H 2 O 2.

show abstract

Facile synthesis of SiO2–Au nanoshells in a three-stage microfluidic system

Cited by 53 publications

References 26 publications

Continuous synthesis of palladium nanorods in oxidative segmented flow

Continuous synthesis of palladium nanorods in oxidative segmented flow

Engineering the synthesis of silica–gold nano-urchin particles using continuous synthesis

Preparation and Optical Properties of PS @Au-Cu Core-Shell Nano Composite

Contact Info

Product

Resources

About