MOF Induces 2D GO to Assemble into 3D Accordion‐Like Composites for Tunable and Optimized Microwave Absorption Performance

Three‐dimensional (3D) materials assembled by 2D layered lamella can provide abundant interfaces which are greatly advantageous for high‐performance microwave absorbers. Herein, accordion‐like CeO2−x/reduced graphene oxide (CeO2−x/RGO) hybrid materials can be successfully synthesized by a solvothermal and hydrothermal method, which are composed of laminated RGO sheets and confined CeO2−x nanoparticles (NPs). The multilayer structure is attributed to the process of Ce‐MOF dissolving into NPs, then the NPs combining with graphene oxide (GO) to induce the 2D GO assembled into 3D accordion‐like composites. The 3D accordion‐like CeO2−x/RGO simultaneously utilizes the insulated CeO2−x and highly conductive RGO to assemble into the laminated structure with moderate electromagnetic parameters. The 3D‐laminated lightweight CeO2−x/RGO composite exhibits excellent attenuation ability of an ultrabroad bandwidth (5.84 GHz) and a maximum reflection loss (−50.6 dB) which can be ascribed from the glorious impedance matching, synergistic effect between RGO sheets and the embedded CeO2−x NPs. An off‐axis electron holography is carried out to visualize the spatial electrical potential and charge distribution around the CeO2−x/RGO heterojunction, which clarifies the dipole polarization and interfacial polarization. This work enlightens a simple strategy to fabricate an excellent 3D laminated RGO‐based microwave absorber.