Sub-millisecond microfluidic mixers coupled to time-resolved <i>in situ</i> photonics to study ultra-fast reaction kinetics: the case of ultra-small gold nanoparticle synthesis - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Lab on a Chip Année : 2024

Sub-millisecond microfluidic mixers coupled to time-resolved in situ photonics to study ultra-fast reaction kinetics: the case of ultra-small gold nanoparticle synthesis

Résumé

We report a continuous microreactor platform achieving sub-millisecond homogeneous reagent mixing (∼300 μs) for a time-resolved study on the synthesis of ultra-small gold nanoparticles (NPs). The microreactor (coupled with small angle X-ray scattering, UV-vis, and X-ray absorption spectroscopy for in situ and in operando characterizations), operates within mixing time frames below system characteristic times, providing a unique opportunity to deepen the comprehension of reaction and phase transition pathways with unprecedented details. The microreactor channel length can be approximated to a given reaction time when operated in continuous mode and steady state. As a result, the system can be statically investigated, eliminating technique-dependent probing time constraints and local inhomogeneities caused by mixing issues. We have studied Au(0) NP formation kinetics from Au(III) precursors complexed with oleylamine in organic media, using triisopropylsilane as a reducing agent. The existence of Au(III)/Au(I) prenucleation clusters and the formation of a transient Au(I) lamellar phase under certain conditions, before the onset of Au(0) formation, have been observed. Taking advantage of the high frequency time-resolved information, we propose and model two different reaction pathways associated with the presence or absence of the Au(I) lamellar phase. In both cases, non-classical pathways leading to the formation of NPs are discussed.
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Dates et versions

hal-04346488 , version 1 (15-12-2023)

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Raj Kumar Ramamoorthy, Ezgi Yildirim, Isaac Rodríguez-Ruiz, Pierre Roblin, Lise-Marie Lacroix, et al.. Sub-millisecond microfluidic mixers coupled to time-resolved in situ photonics to study ultra-fast reaction kinetics: the case of ultra-small gold nanoparticle synthesis. Lab on a Chip, 2024, ⟨10.1039/d3lc00778b⟩. ⟨hal-04346488⟩
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