Novel one-pot sol-gel synthesis route of Fe3C/few-layered graphene core/shell nanoparticles embedded in a carbon matrix

TL;DR

This paper presents a new one-pot sol-gel method to synthesize Fe3C/few-layered graphene core/shell nanoparticles embedded in a carbon matrix, achieving high magnetic response and chemical stability.

Contribution

A novel chemical synthesis route for Fe3C nanoparticles with embedded few-layer graphene, enabling controlled nanostructure formation and enhanced magnetic and chemical stability.

Findings

Fe3C nanoparticles of ~20 nm were successfully synthesized.

The process yields high saturation magnetization (~43 emu/g).

The method produces environmentally stable, passivated nanostructures.

Abstract

Fe3C/few-layered graphene core/shell nanoparticles embedded in a carbon matrix are synthesized by a novel two-step surfactant sol-gel strategy, where the processes of hydrolysis, polycondensation and drying take place in a one-pot. The present approach is based on the combined action of oleic acid and oleylamine, which act sterically on the precursor micelles when a densification temperature is performed in a reducing atmosphere. The structural and magnetic evolution of the formed compounds is investigated, ranging from iron oxides such as Fe3O4 and FeO, to the formation of pure Fe3C/C samples from 700 {\deg}C onwards. Interestingly, Fe3C nanoparticles with a size of ~20 nm crystallize immersed in the carbon matrix and the surrounding environment forms an oriented encapsulation built by few-layered graphene. The nanostructures show a saturation magnetization of ~43 emu/g and a moderate coercivity of ~500 Oe. Thereby, an innovative chemical route to produce single phase Fe3C nanoparticles is described, and an effective method of few-layered graphene passivation is proposed, yielding a product with a high magnetic response and high chemical stability against environmental corrosion.