Simple synthesis of low-load γ-Fe2O3/C/CNT for efficient building absorber

The rapid expansion of 5 G technology and the proliferation of electronic devices have exacerbated electromagnetic radiation pollution of urban building space and pose significant risks to human health, necessitating the development of efficient electromagnetic wave (EMW) absorbing materials for use in buildings to address this challenge. Carbon nanotubes (CNT) and magnetic materials such as Fe are widely used in this field due to their unique electromagnetic properties. In this study, gamma-Fe2O3/C/CNT magnetic nanofibers were successfully prepared, exhibiting synergistic di-electric and magnetic capabilities through electrospinning and mechanical blending methods. Compared to gamma-Fe2O3/C fibers and CNT, the CNT-modified composite material exhibited superior EMW absorption performance. At a low loading of 15 wt%, the gamma-Fe2O3/C/CNT composite fibers achieved a minimum reflection loss (RLmin) of -78.89 dB (2.61 mm) and an effective absorption bandwidth (EAB) of 4.12 GHz (1.52 mm, 13.6-17.72 GHz). The superior EMW absorbing performance is primarily attributed to the three-dimensional network structure created by the intertwined nanofibers and CNT, through the synergy of two one-dimensional structures, which achieved good impedance matching and multiple loss mechanisms. As highefficiency absorbing agents, gamma-Fe2O3/C/CNT magnetic nanocomposite fibers have broad application prospects, serving as low-loading polymer coatings and cement-based materials absorbent to absorb radiation from electronic devices within buildings, reducing indoor electromagnetic pollution, and they can also be used in the field of military stealth. This work provides new insights into the development of efficient EMW absorbing materials.