Enhanced Protection of Carbon-Encapsulated Magnetic Nickel Nanoparticles through a Sucrose-Based Synthetic Strategy

We report an easy synthesis strategy for the incorporation of carbon-coated Ni nanoparticles within the pores of a highly porous carbon matrix. An advantageous feature of this process is that it is able to provide large amounts of magnetic Ni composite by means of an easy-to-follow one-pot reaction. While a typical chemical route based on a conventional pyrolysis procedure gives rise to NPs with Ni@NiO (core@shell structure), the addition of sucrose to the synthesis mixture and its subsequent transformation to carbon endows the Ni-NPs with an effective protection via the formation of a thin carbon layer around the metallic nanoparticles. This protective shell stabilizes the inserted metallic particles by preventing the aerial oxidation of Ni-NPs (i.e., NiO) and their dissolution in an aqueous acid environment. The macroscopic magnetization values of these nanocomposites (up to 6 emu/g) and their superparamagnetic behavior at room temperature allow them to be easily manipulated with conventional magnets. This makes them ideal candidates for use in applications that involve magnetic separation (i.e., heterogeneous catalysis, adsorption of contaminants in aqueous media, etc.).