The remarkable advantages of heterointerface and defect engineering and their unique electromagnetic characteristics inject infinite vitality into the design of advanced carbon-matrix electromagnetic wave absorbers. However, understanding the interface and dipole effects based on microscopic and macroscopic perspectives, rather than semi-empirical rules, can facilitate the design of heterointerfaces and defects to adjust the impedance matching and electromagnetic wave absorption of the material, which is currently lacking. Herein, CuCo₂S₄@Expanded Graphite heterostructure with multiple heterointerfaces and cation defects are reported, and the morphology, interfaces and defects of component are regulated by varying the concentration of metal ions. The results show that the 3D flower-honeycomb morphology, the crystal-crystal/amorphous heterointerfaces and the abundant cation defects can effectively adjust the conductive and polarization losses, achieve the impedance matching balance of carbon materials, and improve the absorption of electromagnetic wave. For the sample CEG-6, the effective absorption of Ku band with RL_min of −72.28 dB and effective absorption bandwidth of 4.14 GHz is realized at 1.4 mm, while the filler loading is only 7.0 wt. %. This article reports on the establishment of potential relationship between crystal-crystal/amorphous heterointerfaces, cation defects, and the impedance matching of carbon materials.

Disposal of the waste from carbon fiber reinforced polymers (CFRPs) has become an urgent problem due to the increasing application of CFRPs in many industries. A novel method for the rapid recovery of carbon fibers by a microwave pyrolysis and oxidation process was proposed in this study. The resin matrix was rapidly pyrolyzed by heating CFRPs directly with microwave radiation, and then the residual carbon and organic matter on the surface of carbon fibers were removed by oxidation to obtain recycled carbon fibers (RCFs). The recovery rate of recycled carbon fibers was measured, and their mechanical properties were evaluated by tensile strength and tensile modulus tests. The results showed that, after microwave pyrolysis at 500 °C for 15 min and oxidation at 550 °C for 30 min, the maximum tensile strength of RCFs was 3042.90 MPa (about 99.42% of that of virgin carbon fibers), the tensile modulus was 239.39 GPa, and the recovery rate was about 96.5%. The microstructure and chemical composition of RCFs were characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, and the components of the pyrolysis byproducts were detected by gas chromatography-mass spectrometry. These results indicate that this method is suitable for the effective recovery of high-quality carbon fibers from CFRPs.

With the growth of the use of carbon fiber-reinforced polymer (CFRP) in various fields, the recovery of carbon fibers from CFRP waste is becoming a significant research direction. In the present work, degrading epoxy resin and recycling carbon fibers from CFRP waste by microwave thermolysis and traditional thermolysis were studied. The carbon fibers were successfully recovered by thermolysis under an oxygen atmosphere in this study. The properties of the recovered carbon fibers were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Raman spectroscopy. The result shows that using microwave thermolysis to recover carbon fibers from CFRP waste is an attractive prospect. Compared to the traditional method, the reaction time was reduced by 56.67%, and the recovery ratio was increased by 15%. Microwave thermolysis is faster, more efficient, requires less energy, and obtains cleaner recovered carbon fibers than those recovered using traditional thermolysis.

Antibiotic wastewater poses a great threat to the ecological environment and human health. Photocatalytic technology is an effective way to solve environmental pollution problems. In recent years, 2D/2D nanocomposites have received widespread attention because of their larger contact area, which can improve photocatalytic activity. However, the rapid synthesis of 2D/2D nanocomposites at low temperatures is still a challenge. Here, we demonstrated a facile one-step approach to synthesize 2D/2D ZnO nanosheet/rGO nanocomposites through microwave heating in a short time (20 min) for photodegradation of tetracycline (TC). Compared to the pure ZnO nanosheets, the ZnO/rGO-2 nanocomposites exhibited best photocatalytic activity under UV light. The enhanced photocatalytic performance could be attributed to introduction of GO nanosheets, which improves the specific surface area and pore structure and enhances the TC adsorption capacity. In addition, due to the interfacial coupling between ZnO and rGO, the charge was rapidly transferred and the recombination of photogenerated electron–hole pairs on the ZnO surface was inhibited. Our present work provided an efficient and low-temperature strategy for designing 2D/2D ZnO nanosheet/rGO photocatalysts and achieved gram-level production, which opens a new path to fabricate 2D/2D nanocomposites using microwave technology.