Introducing defects and crystalline/amorphous heterostructures on mesoporous TiO2 to realize broadband microwave absorption

Titanium dioxide (TiO 2 ), once considered a promising material for microwave absorption, still faces significant challenges in achieving broadband absorption performance. To address this issue, herein, a simple approach is reported for successfully introducing defects and crystalline/amorphous heterostructures onto mesoporous TiO 2 (Meso-am-TiO 2-x ). This study demonstrates the superior microwave absorbing properties of Meso-am-TiO 2-x , particularly in the low-frequency range. A reflection loss of up to −25.7 dB is achieved with a thickness of 4.6 mm, and the effective absorption bandwidth (EAB) value extends to 4.32 GHz. The experimental results indicate that the synergistic effects of the high specific surface area of mesoporous TiO 2 , defects-induced conduction loss, defect-induced dipole polarization loss, and interfacial polarization loss between the crystalline and amorphous heterostructures enhance the microwave absorption properties of Meso-am-TiO 2-x . This study provides insights toward developing innovative low-frequency broadband TiO 2 absorbers.