Achieving precise control over the magnetic properties of composite materials for specific applications, while simultaneously optimizing their magnetic, dielectric, and electrical characteristics, remains a formidable challenge in material science. This study addresses this challenge by systematically modulating the magnetic and electrical properties of ZrO₂/Fe₃O₄-Fe/C nanocomposites through controlled variations in the Zr/Fe ratio and leveraging electron transfer-induced effects. First-principles calculations reveal that reducing the Zr/Fe ratio decreases ZrO₂ content, thereby limiting the transfer of unpaired electrons to ZrO₂. This limitation leads to the accumulation of localized electrons, significantly enhancing the magnetic moments from 136.29 to 165.76 μB. The fine-tuning of the Zr/Fe ratio enables precise electron transfer control, unlocking synergistic optimization of magnetic, dielectric, and electrical properties. Notably, the 4-ZrO₂/Fe₃O₄-Fe/C-700 composite demonstrated exceptional electromagnetic wave absorption performance, achieving a minimum reflection loss (RLmin) of −67.76 dB and an effective absorption bandwidth (EAB) of 6.11 GHz with a thickness of only 2.4 mm. These results not only highlight a breakthrough in tailoring magnetic properties via electron transfer but also advance the understanding of the intricate interplay between magnetic regulation mechanisms and functional properties. This study provides a robust foundation for the development of next-generation magnetic materials with multifunctional applications, which has great application potential in the field of stealth technology.

Oil sorbents are an attractive option for oil-spill cleanup as they may be used for collection and complete removal of oil without adversely affecting the environment. However, traditional oil sorbents exhibit low oil/water separation efficiency and/or low oil-sorption capacity. In this study, an ultra-high performance graphene/polyurethane (PU) sponge has been successfully obtained by in situ polymerization in the presence of graphene dispersed in N-methylpyrrolidone (NMP). During polymerization, the NMP/graphene dispersion not only serves as a weak amine catalyst for the formation of the sponge, but promotes fixation of the graphene sheets in the framework of the PU sponge owing to the strong dipole interaction between NMP and graphene. The as-prepared graphene/PU sponge was used as an absorbing material for the continuous removal of oil from oil-spill water. The graphene/PU sponge can continuously and rapidly remove oils from immiscible oil/water mixtures in corrosive solutions, including strong acids and bases, hot water, and ice water, with an excellent separation efficiency of above 99.99%. In addition, the as-prepared graphene/PU sponge was effective in separating surfactant-stabilized emulsions with a high separation efficiency of > 99.91%.

Self-healing superhydrophobic polyvinylidene fluoride/Fe₃O₄@polypyrrole (F-PVDF/Fe₃O₄@PPy_x ) fibers with core–sheath structure were successfully fabricated by electrospinning of a PVDF/Fe₃O₄ mixture and in situ chemical oxidative polymerization of pyrrole, followed by chemical vapor deposition with fluoroalkyl silane. The F-PVDF/Fe₃O₄@PPy_0.075 fiber film produces a superhydrophobic surface with self-healing behavior, which can repetitively and automatically restore superhydrophobicity when the surface is chemically damaged. Moreover, the maximum reflection loss (R_L) of the F-PVDF/Fe₃O₄@PPy_0.075 fiber film reaches -21.5 dB at 16.8 GHz and the R_L below -10 dB is in the frequency range of 10.6–16.5 GHz with a thickness of 2.5 mm. The microwave absorption performance is attributed to the synergetic effect between dielectric loss and magnetic loss originating from PPy, PVDF and Fe₃O₄. As a consequence, preparing such F-PVDF/Fe₃O₄@PPy_x fibers in this manner provides a simple and effective route to develop multi-functional microwave absorbing materials for practical applications.