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

Abstract

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 CeO_2- _x /reduced graphene oxide (CeO_2- _x /RGO) hybrid materials can be successfully synthesized by a solvothermal and hydrothermal method, which are composed of laminated RGO sheets and confined CeO_2- _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 CeO_2- _x /RGO simultaneously utilizes the insulated CeO_2- _x and highly conductive RGO to assemble into the laminated structure with moderate electromagnetic parameters. The 3D-laminated lightweight CeO_2- _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 CeO_2- _x NPs. An off-axis electron holography is carried out to visualize the spatial electrical potential and charge distribution around the CeO_2- _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.