Effect of nitric acid treatment on the final low-frequency microwave absorption performance of TiO₂/ZnFe₂O₄/ZnTiO₃ nanocomposite

With the fast development of electronic technique, abundant microwave radiation and interference affect the human’s health deeply. Here, a novel low-frequency microwave absorbent of TiO₂/ZnFe₂O₄/ZnTiO₃ nanocomposite was prepared via a combinative route of sol–gel, solvothermal and calcination. The electromagnetic wave-absorbing properties of this ternary nanocomposite are closely related to the pre-treated concentration of TiO₂ with nitric acid. The suitable concentration can promote the final absorption performance due to the increasing surface groups and defects for enhanced dipole polarization. The interface polarization between anatase and rutile TiO₂ also contributes a lot to the absorption effect. Additionally, the natural resonance, eddy current, multiple scattering and good impedance match play a significant effect as well. Thus, the excellent microwave-absorbing ability of as-prepared composite generates from the synergy effectiveness of magnetic and dielectric losses. The optimal reflection loss reaches −45.3 dB at 1.19 GHz with EAB of 0.82 ~ 1.67 GHz for 3.5 mm, and the widest efficient absorbing bandwidth achieves 1.5 GHz at only 1.5 mm. The investigation reported here provides a novel route to adjust the microwave absorption capability of TiO₂-based MAMs in low-frequency band.