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

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.