High Temperature Preparation of Core and Core/Shell Composite Nanocrystals in a Multiphase Microreactor

Lee, Chan-Gi; Uehara, Masato; Nakamura, Hiroyuki; Maeda, Hideaki

doi:10.1252/jcej.07we116

Cited by 10 publications

(13 citation statements)

References 18 publications

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“…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

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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.

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Section: Introductionmentioning

confidence: 99%

Continuous synthesis of palladium nanorods in oxidative segmented flow

2015

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“…Most of the above reactions were carried out in segmented flow reactors operating at room temperature (with the liquid/gas CdSe syntheses by Yen et al43 and Lee et al . 35 being exceptions). Reactors that can operate at high temperatures are desirable as they allow for a broader range of reaction conditions and synthetic methods, and lead to increased particle crystallinity due to enhanced annealing.…”

Section: Segmented Flow Regimesmentioning

confidence: 97%

“…In the ten years since the first reported synthesis of nanocrystals in a microreactor10 there has been an explosion of activity in the application of flow reactors to the small‐scale (<1 g) synthesis of high quality nanoparticles. Nanocrystalline colloids of a wide range of materials have been synthesised including (but not limited to) CdSe,11–13 CdS,10, 14 InP,15 Ag,16 Au,17 Co,18 TiO 2 ,19–21 SiO 2 ,22 LaPO 4 ,23 CaCO 3 ,24 Fe x O y ,25, 26 zeolites27, 28 and BaSO 4 ,29, 30 as well as more complicated core/shell structures such as CdSe/ZnS,31 Fe 2 O 3 /SiO 2 ,32 SiO 2 /Au,33 Au/Ag/Au34 and CdSe/ZnSe/ZnS 35. In all cases, flow reactors have been shown to offer significant advantages over equivalent batch reactions, most notably in terms of increased reaction control and the ability to fine tune the final product.…”

Section: Microreactors For Nanocrystal Synthesismentioning

confidence: 99%

“…This is consistent with the removal of dispersion and the enhanced cross‐channel mixing that is obtained with slug flow, leading to improved monodispersity. More recently, Lee et al35 reported the segmented flow synthesis of CdSe using very similar chemistry, but an alternative strategy to generate gas/liquid segmented flow: by adding a volatile short‐chain amine to their CdSe precursor solution, a gaseous phase was generated in‐situ during heating, resulting in the narrowing of the photoluminescence emission line‐width from 48.2 nm (without amine) to 25.6 nm (with).…”

Section: Segmented Flow Regimesmentioning

confidence: 99%

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Segmented Flow Reactors for Nanocrystal Synthesis

2012

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In the past decade microreactors have emerged as a compelling technology for the highly controlled synthesis of colloidal nanocrystals, offering multiple advantages over conventional batch synthesis methods (including improved levels of control, reproducibility, and automation). Initial work in the field employed simple continuous phase reactors that manipulate miscible streams of a single reagent phase. Recently, however, there has been increasing interest in segmented flow reactors that use an immiscible fluid to divide the reagent phase into discrete slugs or droplets. Key advantages of segmented flow include the elimination of velocity dispersion (a significant cause of polydispersity) and greatly reduced susceptibility to reactor fouling. In this progress report we review the operation of segmented flow microreactors, their application to the controlled synthesis of nanocrystals, and some of the principal challenges that must be addressed before they can become a mainstream technology for the controlled production of nanomaterials.

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“…Khan et al., 2007 Lee et al., 2008 Yang et al., 2009 Abou‐Hassan et al., 2009 Duraiswamy et al., 2010 Kikkeri et al., 2010 Lan et al., 2011 Wan et al., 2011 Fang et al., 2010 Duraiswamy et al., 2010…”

Section: Application Of Flow Reactors; Toward Hybrids With Tailor‐madmentioning

confidence: 99%

Precise Synthesis of Well‐Defined Inorganic‐Organic Hybrid Particles

Shiba

Ogawa

2018

The Chemical Record

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Synthesis of hybrid particles toward precisely designed hierarchical nanoarchitectures is summarized. In order to satisfy the demands for a variety of materials' performances, the selection of materials, composition and synthesis is carefully done. Flow reactors are one of the useful synthetic means to prepare hybrid materials, especially those with hierarchically and precisely designed multi-components hybrid particles, owing to the efficient mixing and heat exchange in the reactor as well as its connectable (both parallel and sequential) feature. In this review article, after the summary of the preparation of hybrids based on oxides and organics through conventional batch reactors, the application of flow reactors to the preparation of various hybrid particles is introduced to highlight the present status and future possibility of the flow reactor synthesis.

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High Temperature Preparation of Core and Core/Shell Composite Nanocrystals in a Multiphase Microreactor

Cited by 10 publications

References 18 publications

Continuous synthesis of palladium nanorods in oxidative segmented flow

Continuous synthesis of palladium nanorods in oxidative segmented flow

Segmented Flow Reactors for Nanocrystal Synthesis

Precise Synthesis of Well‐Defined Inorganic‐Organic Hybrid Particles

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