Microreactors for Gold Nanoparticles Synthesis: From Faraday to Flow

Abstract

Abstract:The seminal work of Michael Faraday in 1850s transmuted the "Alchemy of gold" into a fascinating scientific endeavor over the millennia, particularly in the past half century. Gold nanoparticles (GNPs) arguably hold the central position of nanosciences due to their intriguing size-and-shape dependent physicochemical properties, non-toxicity, and ease of functionalization and potential for wide range of applications. The core chemistry involved in the syntheses is essentially not very different from what Michael Faraday resorted to: transforming ions into metallic gold using mild reducing agents. However, the process of such reduction and outcome (shapes and sizes) are intricately dependent on basic operational parameters such as sequence of addition and efficiency of mixing of the reagents. Hence, irreproducibility in synthesis and maintaining batch-to-batch quality are major obstacles in this seemingly straightforward process, which poses challenges in scaling-up. Microreactors, by the virtue of excellent control over reagent mixing in space and time within narrow channel networks, opened a new horizon of possibilities to tackle such problems to produce GNPs in more reliable, reproducible and scalable ways. In this review, we will delineate the state-of-the-art of GNPs synthesis using microreactors and will discuss in length how such "flask-to-chip" paradigm shift may revolutionize the very concept of nanosyntheses.

Synthesis of Gold Nanoparticles Using the Interface of an Emulsion Droplet

“…These have all been found to influence the products. An extensive review on the subject is covered elsewhere 37 and have been extensively applied to the production of AuNPs 38 .…”

“…organic) and a metal precursor in the second phase (e.g. aqueous) as shown in (Figure 1Di) and a wide range of synthetic strategies at these interfaces have been reported 37,38,59,60 .…”

Synthesis of palladium nanoparticles using continuous flow microreactor

“…Microreactors offer a small volume for the reaction, which allows precise control over the synthesis of nanoparticles such as palladium (Pd), platinum (Pt) and gold (Au) etc. [16][17][18]. Rebrove et al [19] have shown that a microreactor system increases the heat transfer within the reaction mixture and hence improves the reaction kinetics.…”

Special Issue: Design and Engineering of Microreactor and Smart-Scaled Flow Processes

“…Exactly this is the focus of the current special issue "Design and Engineering of Microreactor and Smart-Scaled Flow Processes" of the journal "Processes". This special issue comprises three review papers, five research articles and two communications.Rahman and Rebrov have presented an overview of the application of microreactors in the synthesis of gold nanoparticles (GNP) [1]. Considering that reactant mixing is one of the most critical factors influencing the GNP synthesis, batch operating conditions commonly pose great limitations to both quality and scalability of the process.…”

“…Rahman and Rebrov have presented an overview of the application of microreactors in the synthesis of gold nanoparticles (GNP) [1]. Considering that reactant mixing is one of the most critical factors influencing the GNP synthesis, batch operating conditions commonly pose great limitations to both quality and scalability of the process.…”