Non-conventional Fe3C-based nanostructures

Abstract

Novel Fe₃C-based nanostructures with an inner layered structure have been synthesized by a simple medium-temperature (T = 700 °C) process based on carbothermal reduction. In this process, the iron precursor reacts with a selected nitrogen rich carbon source (namely, 4,5-dicyanoimidazole) to form wrapped nano-sheets of Fe₃C@C(N). The nanosheets are composed of 5 nm crystalline Fe₃C nanoparticles, which are integrated into a nitrogen-doped carbon phase giving rise to the wrapped morphology. By variation of reaction parameters (such as initial concentration, temperature, reaction time), the typical accompanying side products of iron carbide such as metallic iron and amorphous carbon can be kept very low or even avoided. Contrary to simple expectations, those nanostructures are surprisingly robust against oxidation in air and could have potential applications in nanomagnetism and catalysis.