Three-Dimensional Macroporous Reduced Graphene Oxide-Mxene Aerogel Decorated with Hollow Mesoporous Carbon Spheres for Absorption-Dominant Electromagnetic Interference Shielding and Efficient Oil/Water Separation

Herein, hollow mesoporous carbon sphere (HMCS)/Mxene/rGO aerogels were fabricated by simple hydrothermal reduction self-assembly and freeze-drying treatment. Owing to the unique hollow mesoporous architecture, the HMCS nanoparticles can offer additional incident channels and absorption cavities, enhancing the electromagnetic wave (EMW) loss capacity. Moreover, the fabrication of 3D porous structures and the synergy of multiple losses can extremely reduce impedance mismatching, resulting in more EMWs to incident into the matrix for consumption. In addition, abundant heterointerfaces between rGO, Mxene, and HMCSs lead to the formation of multiple polarization losses, which further improve the electromagnetic interference shielding efficiency (EMI SE). Therefore, benefiting from the hierarchical 3D porous architecture, cooperative electromagnetic wave loss mechanism, and multiple heterointerfaces, the resultant EMI SE of the rGO-Mxene-HMCS aerogel reaches 80 dB at 8.2-12.4 GHz, which is 2.5 times that of the pure rGO aerogel. More interestingly, owing to their hydrophobicity and promising hierarchical porous structure, rGO-Mxene-HMCS composites can efficiently select and adsorb various oils and organic solvents in oil/water mixtures to realize oil/water separation. Remarkably, the rGO-Mxene-HMCS aerogel exhibits an impressive absorption capacity of up to 100-160 times its weight, and it also shows admirable absorption recyclability. Thus, the rGO-Mxene-HMCS aerogel exhibits great potential in the application of electromagnetic shielding and oil/water separation.