A Microfluidic Device for the Investigation of Rapid Gold Nanoparticle Formation in Continuous Turbulent Flow

Hofmann, G.; Tofighi, Ghazal; Rinke, Günter; Baier, Sina; Ewinger, A.; Urban, Alexander S.; Wenka, A.; Heideker, S.; Jahn, Α.; Dittmeyer, Roland; Grunwaldt, Jan‐Dierk

doi:10.1088/1742-6596/712/1/012072

Cited by 6 publications

(6 citation statements)

References 13 publications

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“…In order to synthesize highly monodisperse metal NPs via fast reduction reactions, a novel microfluidic setup capable of generating a continuous and pulsation-free flow of reactants at high flow rates was used , (Figure ). The fluid delivery rack consists of 4 L corrosion-resistant stainless steel vessels (polyethylene inner coating for metal precursor vessel) pressurized by 13 bar of N 2 gas to deliver the reactants at 2.6 L h –1 total flow rate to three cyclone micromixers integrated in a microfluidic chip for fast (2 ms) and homogeneous mixing.…”

Section: Experimental Methodsmentioning

confidence: 99%

Microfluidic Synthesis of Ultrasmall AuPd Nanoparticles with a Homogeneously Mixed Alloy Structure in Fast Continuous Flow for Catalytic Applications

et al. 2018

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Ultrasmall Au, Pd, and AuPd nanoparticles (NPs) stabilized by PVP were prepared in a microfluidic reactor with cyclone micromixers for rapid mixing of reactants. In this system, pulsation-free flow of reactants was achieved at a total flow rate of 2.6 L h–1. A rapid homogeneous mixing within 2 ms was obtained with three cyclone micromixers. Controlled NP nucleation and growth occur in a following meandering microchannel. The resulting colloidal NPs were characterized thoroughly by various complementary techniques, e.g., high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), and ultraviolet–visible spectroscopy. The average NP diameter was about 1 nm with a narrow size distribution, and electron microscopy showed homogeneously alloyed NPs. Moreover, the particles were supported on TiO2 for catalytic tests and further structural characterization. Electron microscopy showed a uniform distribution of NPs on the support with some aggregation. X-ray absorption spectroscopy (XAS) confirmed the formation of well-mixed AuPd alloys in NP cores with Pd-rich surfaces. Finally, 1 wt % metal-loaded supports showed catalytic activities in CO oxidation in the following order: Au/TiO2 ≥ Au x Pd y /TiO2 ≥ Pd/TiO2. Hence, the physical and chemical properties of these catalysts can be fine-tuned.

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Section: Experimental Methodsmentioning

confidence: 99%

Microfluidic Synthesis of Ultrasmall AuPd Nanoparticles with a Homogeneously Mixed Alloy Structure in Fast Continuous Flow for Catalytic Applications

et al. 2018

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“…The four independent variables x 1 – x 4 assessed for their effects on AuNP synthesis include the concentration ratio of sodium citrate to chloroauric acid ( C ), the pH of the chloroauric acid solution, the reaction temperature ( T ), and Reynolds number ( Re ). These four variables were chosen based on their reported significant influence on the reaction outcomes (e.g., particle size and distribution, phase purity of product, particle shape) in AuNP synthesis, both in batch reactors and microfluidic platforms 6, 8, 11, 15, 23–25. The optimum ranges of T (25 °C–80 °C) and Re (1–20) were set by the limitations of the PDMS mixer, whereas C (1:1 to 1:10) and pH (3–11) were chosen based on literature for AuNP synthesis.…”

Section: Methodsmentioning

confidence: 99%

“…Microfluidic reactors have recently been implemented to synthesize AuNPs with better control on particle characteristics and properties 5–12. These miniaturized reactors, usually micromixers, present faster heat transfer, provide quick and improved mixing between reactants 13, 14, and are easy to design, scale up, and manipulate.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Gold Nanoparticle Synthesis in Continuous‐Flow Micromixers Using Response Surface Methodology

et al. 2021

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Gold nanoparticles (AuNPs) were synthesized in microfluidic mixers by means of response surface methodology (RSM). A reverse‐staggered herringbone micromixer was employed and reaction temperature, concentration ratio of reactants, Reynolds number, and pH of chloroauric acid were varied, with desired responses being particle size and peak intensity from UV spectroscopy. RSM was performed by simultaneously optimizing variable ranges to identify the best fit of polynomial equations to experimental data. Results revealed the individual and synergistic roles of each reaction variable on particle size and UV peak intensity, leading to identification of the largest design space. The effect of reaction variables on AuNP synthesis and particle size was confirmed in serpentine mixers.

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“…There are a few examples of using microfluidic systems coupled with XAS, which were aimed at achieving the time evolution of the systems under investigation via space-resolved measurements. A group of Grunwaldt monitored the formation of gold nanoparticles by progressive decrease of the white line in Au L 3 -edge X-ray absorption near-edge structure (XANES) spectra, indicative of the reduction process. Variation of iron oxidation state during the reaction of iron(II) chloride with NaOH was monitored by Fe K -edge XANES at the SOLEIL synchrotron .…”

Section: Introductionmentioning

confidence: 99%

High-Quality In Situ X-ray Absorption Spectroscopy Monitoring of the Palladium Nucleation inside the 3D Printed Microfluidic Chip

Dobrovolskaya,

Chapek,

Usoltsev

et al. 2023

J. Phys. Chem. C

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An efficient approach for high-quality X-ray absorption spectroscopy (XAS) measurements is proposed and exemplified by monitoring the nucleation of palladium nanoparticles from Pd(II) acetate. The idea of an X-ray beam passing through a microfluidic channel allowed for a significant improvement of the data quality to monitor in situ the early stages of palladium nanoparticle formation. The time evolution of Pd(II) and Pd(0) fractions was followed by collecting the spectra in seven subsequent channels and quantified by linear combination analysis of Pd foil and Pd acetate reference spectra. This work illustrates the application of XAS in microfluidics for chemical systems and might be used for obtaining structural information under reaction conditions in the presence of 4d metals.

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A Microfluidic Device for the Investigation of Rapid Gold Nanoparticle Formation in Continuous Turbulent Flow

Cited by 6 publications

References 13 publications

Microfluidic Synthesis of Ultrasmall AuPd Nanoparticles with a Homogeneously Mixed Alloy Structure in Fast Continuous Flow for Catalytic Applications

Microfluidic Synthesis of Ultrasmall AuPd Nanoparticles with a Homogeneously Mixed Alloy Structure in Fast Continuous Flow for Catalytic Applications

Optimization of Gold Nanoparticle Synthesis in Continuous‐Flow Micromixers Using Response Surface Methodology

High-Quality In Situ X-ray Absorption Spectroscopy Monitoring of the Palladium Nucleation inside the 3D Printed Microfluidic Chip

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