Yolk-Shell Fe ₃ O ₄ @Void@N-Carbon Nanostructures Based on One-Step Deposition of SiO ₂ and Resorcinol-3-Aminophenol-Formaldehyde (R-APF) Cocondensed Resin Dual Layers onto Fe ₃ O ₄ Nanoclusters

Yolk-shell magnetic nanoparticles@nitrogen-enriched Carbon nanostructures with a magnetic core and a hollow nitrogen-enriched carbon shell exhibit considerable promise in various applications, such as drug delivery, heterogenous catalysts, removal of metal ions and organic pollutants, and screening of biomolecules, due to their strong magnetic response, unique cavities, and the selective absorption ability of nitrogen-enriched groups. However, their complicated synthesis always involves possible surface modification, layer-by-layer deposition of a sacrificial middle layer and an outer nitrogen-enriched layer on magnetic nanoparticles, subsequent carbonization, and final removal of the sacrificial middle layer. Herein, yolk-shell Fe₃ O₄ @nitrogen-enriched carbon nanostructures are constructed based on NH₄ ⁺ ion-induced one-step deposition of SiO₂ and Resorcinol-3-aminophenol-formaldehyde cocondensed resin (R-APF) dual layers onto poly acrylic acid-modified Fe₃ O₄ nanoclusters without any extra surface modification. The N-Carbon shell thickness of the yolk-shell Fe₃ O₄ @Void@N-Carbon nanostructure can be finely tailored though tailoring the feeding amount of aminophenol and resorcinol to tune the thickness of the outer R-APF resin shell onto Fe₃ O₄ @SiO₂ intermediate particles. This NH₄ ⁺ ion-induced one-pot deposition of double layers can effectively promote synthesis efficiency of this kind of yolk-shell nanostructure.

Keywords: magnetic nanoparticles; nanocomposites; nitrogen-enriched carbon; one-step deposition; yolk-shell.