Scalable synthesis of dispersible iron carbide (Fe3C) nanoparticles by ‘nanocasting’

Abstract

Metal carbides have shown great promise in a wide range of applications due to their unique catalytic, electrocatalytic and magnetic properties. However, the scalable production of dispersible metal carbide nanoparticles remains a challenge. Here, we report a simple and scalable route to dispersible iron carbide (Fe₃C) nanoparticles. This uses MgO nanoparticles as a removable ‘cast’ to synthesize Fe₃C nanoparticles from Prussian blue (KFe^III[Fe^II(CN)₆]). Electron tomography demonstrates how nanoparticles of the MgO cast encase the Fe₃C nanoparticles to prevent sintering and agglomeration during the high-temperature synthesis. The MgO cast is readily removed with ethylenediaminetetraacetic acid (EDTA) to generate Fe₃C nanoparticles that can be used to produce a colloidal ferrofluid or dispersed on a support material.