Cost-effective synthesis of stable CoxC@few-layered graphene nanostructures embedded in a carbon matrix

Abstract

In this study, a two-step surfactant sol-gel strategy is developed to synthesize Co particles with confined sizes in the nanoscale using organic precursors. This approach does not require the use of vacuum techniques or strong reducing atmospheres, making it a simple approach economically attractive. The strategy involves the generation of few-layered graphene shells to provide chemical stability, prevent oxidation and aggregation tendencies. Additionally, the study investigates the use of precursors based on nitrates and acetates, exploring their structural and magnetic properties in densified samples. Remarkably, magnetic properties are competitive for both approaches, with coercivities reaching up to 300Oe and saturation magnetization of ∼60 and ∼80emu/g for samples based on nitrates and acetates prepared at 650 °C, respectively. However, it is observed that smaller and more uniformly sized nanoparticles (around ∼10nm) are obtained with nitrate-based precursors due to an effective ligand decomposition process. Therefore, this chemical approach offers effective nanoscale confinement with intriguing magnetic properties through a cost-effective and reproducible synthesis.