High Temperature Continuous Flow Syntheses of Iron Oxide Nanoflowers Using the Polyol Route in a Multi-Parametric Millifluidic Device.

Enzo Bertuit,Sophie Neveu,Ali Abou-Hassan

doi:10.3390/nano12010119

Abstract

One of the most versatile routes for the elaboration of nanomaterials in materials science, including the synthesis of magnetic iron oxide nanoclusters, is the high-temperature polyol process. However, despite its versatility, this process still lacks reproducibility and scale-up, in addition to the low yield obtained in final materials. In this work, we demonstrate a home-made multiparametric continuous flow millifluidic system that can operate at high temperatures (up to 400 °C). After optimization, we validate its potential for the production of nanomaterials using the polyol route at 220 °C by elaborating ferrite iron oxide nanoclusters called nanoflowers (CoFe2O4, Fe3O4, MnFe2O4) with well-controlled nanostructure and composition, which are highly demanded due to their physical properties. Moreover, we demonstrate that by using such a continuous process, the chemical yield and reproducibility of the nanoflower synthesis are strongly improved as well as the possibility to produce these nanomaterials on a large scale with quantities up to 45 g per day.

Highlights

In the field of nanomaterials synthesis, a large number of microfluidic reactors have been developed to carry chemical synthesis in a greener and safer way starting from ambient temperature to high-temperature and high-pressure supercritical systems allowing the production of a large panel of high-quality nanoparticles (NPs) [6,7,8,9,10,11,12,13,14,15,16]
We describe for the first time the continuous flow production of magnetic iron oxide ferrite nanoflowers (CoFe2 O4, Fe3 O4, MnFe2 O4 ) by using the polyol route and a home-made multi-parametric millifluidic device which enables continuous-flow syntheses at high temperature with great production capacities
A schematic representation of the multi-parametric and high temperature millifluidic device is shown on Figure 1a–g

Summary

Introduction

Decreasing the dimensions of the chemical reactor was found to be a solution to improve mass and heat transfer of the reactive media, minimizing the undesired gradients often encountered in bulk [1,2,3,4,5]. Despite their small size, high production capacities can be reached in such reactors when chemical syntheses are performed under continuous-flow conditions, often called milli/micro/nano-fluidic syntheses. In the field of nanomaterials synthesis, a large number of microfluidic reactors have been developed to carry chemical synthesis in a greener and safer way starting from ambient temperature to high-temperature and high-pressure supercritical systems allowing the production of a large panel of high-quality nanoparticles (NPs) [6,7,8,9,10,11,12,13,14,15,16]

Methods

Results

Conclusion