Facile aqueous synthesis and electromagnetic properties of novel 3D urchin-like glass/Ni–Ni3P/Co2P2O7 core/shell/shell composite hollow structures

Abstract

Novel 3D urchin-like glass/Ni–Ni₃P/Co₂P₂O₇ core/shell/shell composite hollow structures are fabricated for the first time by controlled stepwise assembly of granular Ni–Ni₃P alloy and ribbon-like Co₂P₂O₇ nanocrystals on hollow glass spheres in aqueous solutions at mild conditions. It is found that the shell structure and the overall morphology of the products can be tailored by properly tuning the annealing temperature. The as-obtained composite core/shell/shell products possess low density (ca. 1.18 g cm⁻³) and shape-dependent magnetic and microwave absorbing properties, and thus may have some promising applications in the fields of low-density magnetic materials, microwave absorbers, etc. Based on a series of contrast experiments, the probable formation mechanism of the core/shell/shell hierarchical structures is proposed. This work provides an additional strategy to prepare core/shell composite spheres with tailored shell morphology and electromagnetic properties.