Dual-gradient Mo2C-decorated rGO aerogels for enhanced electromagnetic wave absorption

The lightweight, strong absorption, non-resin, and high chemical and thermal stability of electromagnetic wave absorption materials used in space vehicles are required in the harsh space environments. Herein, a light weight and effective microwave-absorbing material is constructed by synthesizing carbide-modified reduced graphene oxide (rGO) aerogels, gradient design and carbonization. The as-prepared aerogel material consists of molybdenum carbide (MC) and rGO, and displays hollow structures with multi-wall rGO layers. The MC structure in the MC/rGO aerogel is regulated by controlling the amount of Mo source, and the dual gradient structure composed of MC/rGOmaterial is designed and optimized by CST Microwave Studio. Compared with MC/rGO aerogel, the dual-gradient MC/rGO (DG-MC/rGO) aerogel exhibits superior impedance matching and significantly enhanced microwave absorption performance. The minimum reflection loss (-62.4 dB) is reduced by 64.6%, and the effective absorption bandwidth (5.7 GHz) is increased by over 35.7% at a thickness of 2.2 mm. The remarkable improvement of microwave absorption is attributed to the synergy effect of well-dispersed molybdenum carbide nanoparticles and the components/structures gradients of DG-MC/rGO material. This novel lightweight material has promising applications in electromagnetic wave absorption fields.