Synthesis of hollow-spherical-structured HfB2 with superior electromagnetic wave absorption performance

Various hollow structured HfB 2 powders were synthesized via a co-precipitation assisted boron/carbon thermal reduction method, and the influence mechanism of carbon source on morphology was systematically investigated. When glucose or inositol was employed as the carbon source, the hexagonal ring structure formed in the precursor during complexation directed the growth of HfB 2 nanoparticles that were anchored on hollow spherical carbon templates, resulting in a unique hollow core-shell architecture. Additionally, the morphology could be precisely adjusted from hollow spherical to hollow rod-like structures by simply controlling the stirring temperature during complexation. The growth process of HfB 2 with various morphologies was elucidated, and the mechanism of this unique morphological evolution was revealed to originate from the structural differences of precursor complexes. The HfB 2 powders with hollow spherical structure derived from glucose exhibits excellent electromagnetic absorption ability due to the synergistic effect of multiple scattering and interface polarization within the unique hollow structure, with a maximum reflection loss (RL) of −57.8 dB. Quantitative analysis of the loss mechanisms further demonstrates that the outstanding absorption performance is predominantly governed by polarization loss rather than conduction loss.