Despite the extensive research conducted on dielectric–magnetic coupling in metal-organic frameworks (MOF)-derived absorbers, the underlying mechanisms associated with defects, interfaces, and orbital hybridization remain inadequately investigated. To address this, we developed coral-like MOF-derived nickel–phosphorous@carbon (NP@C) nanocomposites by adjusting the pyrolysis temperature, revealing for the first time the link between structure and electromagnetic (EM) performance. The composite features nickel phosphide nanoparticles (Ni₁₂P₅ core/Ni₂P shell) embedded in an amorphous carbon matrix, where a unique crystal orientation and interfacial coupling enhance EM wave dissipation. The calculations show that charge transfer (0.66e) at the C–Ni₁₂P₅ interface increases conductance loss, whereas the C–Ni₂P–Ni₁₂P₅ heterostructure generates interfacial polarization and defect states via negative charge transfer (0.20e), synergistically enhancing dielectric and magnetic loss. Electronic structure analysis revealed that sharp Ni 3d orbital peaks near the Fermi level coexist with broad carbon matrix peaks, enabling both conductive and spin-related magnetic loss mechanisms. The NP@C nanocomposite achieves a reflection loss of −54.1 dB and an effective absorption band covering 4.1 GHz at a thin thickness of 1.37 mm. This study clarifies the atomic- and electronic-level EM response mechanisms of MOF-derived carbon materials, offering new insights for designing high-performance absorbers.

The semi-transparency to thermal radiation, coupled with low nanoparticle retention and formation of semi-melted particles during plasma spraying, significantly limits the high-temperature application of nanostructured yttria stabilized zirconia (YSZ) (nYSZ) thermal barrier coatings. To address these challenges, this study introduces an innovative approach that involves coating nanoparticles with carbon films to prevent them from melting and merging during the plasma spraying process. This method substantially increases the nanoparticle content within the coating, and nanopores formed at the nanoparticle surfaces when the carbon film is removed at 800 °C. These nanopores, in combination with nanoparticles, enhance thermal radiation scattering, improving the scattering coefficient and thermal radiation blocking capability of the coating. In contrast to that of conventional thermal barrier coatings (TBCs) of YSZ, the simulated temperature of the substrate under service conditions decreases by up to 26.26 K due to decreased radiative heat transfer and by 111.2 K when the thermal conductivity is reduced. Additionally, the scattering coefficients remain stable within the 1–5 μm range even after heat treatment at 1300 °C for 100 h, as the coarsened nanoparticle size approaches the wavelength of thermal radiation. Thus, nYSZ TBCs with enhanced thermal radiation blocking ability and high temperature stability can be created by this approach for higher temperature applications.

Single Ti₃C₂T_x MXene (MTO) materials are not suitable for electromagnetic (EM) wave absorption due to their high conductivity and impedance mismatch. To address this issue, we ingeniously took advantage of easily oxidized characteristics of Ti₃C₂T_x MXene to establish structural defects and multiphase engineering in accordion-like Ti_xO_2x−1 derived from Ti₃C₂T_x MXene by a high-temperature hydrogen reduction process for the first time. Phase evolution sequences are revealed to be Ti₃C₂T_x MXene/anatase TiO₂ → Ti₃C₂T_x MXene/rutile TiO₂ → Ti_xO_2x−1 (1 ≤ x ≤ 4) during a hydrogen reduction reaction. Benefiting from conductance loss caused by hole motion under the action of an external electric field and heterointerfaces caused by interfacial polarization, the impedance match and EM attenuation capability of accordion-like Ti_xO_2x−1 absorbers derived from Ti₃C₂T_x MXene are superior to that of pristine Ti₃C₂T_x MXene/TiO₂ materials. Additionally, simulated whole radar cross section (RCS) plots in different incident angular of the Ti₃C₂T_x MXene/rutile TiO₂ product are lower than −20 dBm², and the minimum RCS value can reach −43 dBm², implying a great potential for practical applications in the EM wave absorption. Moreover, the relationship among charges, defects, interfaces, and EM performances in the accordion-like Ti_xO_2x−1 materials is systematically clarified by the energy band theory, which is suitable for the research of other MXene-derived semiconductor absorbing composites.