Hetero‐Interface Engineering on 9.0 wt% CoOx‐Doped CeO2 Nanorods as Electromagnetic Wave Absorber and Integrated into Multifunctional Aerogel

Abstract Ceria (CeO 2 ) becomes a promising candidate as electromagnetic wave absorbing materials (EWAMs) for their abundant natural source, rich oxygen vacancy, charge conversion, and electron transfer abilities. However, it remains challenging to regulate its nanoscale and atom‐scale composition to optimize the absorbing performance and develop high‐performance commercial devices. Herein, a facile method to large‐scale synthesis CeO 2 @Co‐x% (x = 5, 7, 9, 11, 13) series EWAMs with diverse amounts of decorated CoO x is presented. By modulating the ratio of doped CoO x , a rational hetero‐interface is created in CeO 2 @Co‐9% to enhance natural and exchange resonances, improving magnetic loss capability and optimizing impedance matching. Doped CoO x promotes the charge accumulation, interfacial polarization, and multiple scattering of the CeO 2 for strengthening the EW absorption and attenuation, which display superb minimum reflective loss ( RL min ) of −74.4 dB with a wide effective absorbing bandwidth (EAB) of 5.26 GHz. Furthermore, a dual crosslinking strategy is employed to fabricate CeO 2 @Co‐9% into an aerogel device with integrated lightweight, heat insulation, compression resistance, and fame‐retardant functions. This work presents an excellent example of large‐scale fast synthesis of high‐performance CeO 2 ‐based EWAMs and multiplication 3D devices.