Search

High entropy alloys (HEAs) are promising electromagnetic wave absorption (EMA) materials due to its designable crystal structure, variable electromagnetic properties, and excellent corrosion resistance. However, the impedance mismatch owing to the high electric and dielectric conductivity severely hinders the application of HEAs in the field of EMA. Herein, the lattice distortion of FeCoNiCu HEA is manipulated accurately by doping and annealing strategies to tailor the EMA properties. Significant lattice distortion is observed in the FeCoNiCuC0.37, which leads to a decrease in the electrical conductivity and the creation of abundant dipoles. Owing to the optimal impedance matching and boosted polarization loss, the FeCoNiCuC0.37 delivers a minimal reflection loss of −65.4 dB accompanied by an effective absorption bandwidth (EAB) of 6.81 GHz. After annealing at 200 °C, the EAB of the FeCoNiCuC0.37 is further increased to 7.99 GHz at 1.95 mm, which is better than that of most HEA‐based EMA absorbers reported so far. Moreover, it demonstrates excellent corrosion resistance owing to the more tortuous diffusion path of corrosive medium origin from lattice distortion. Thus, the study provides a new insight into designing high performance HEA‐based EMA materials with superior anti‐corrosion property by lattice distortion engineering. [ABSTRACT FROM AUTHOR]

In this work, novel microbial yeast-decorated zeolitic imidazolate framework-8 (ZIF-8/yeast) composites were successfully synthesized by an in situ growth method and applied in the efficient elimination of Eu(III) from a water medium. The adsorption performances and interaction mechanisms of Eu(III) by ZIF-8/yeast were determined by macroscopic experimental tests under diverse water chemistry conditions. The experimental results indicated that the adsorption performance of Eu(III) on ZIF-8/yeast hybrids could reach equilibrium within 15 min, which conformed to the pseudo-second-order kinetic pattern. The maximum adsorption capacity was 1.09 × 10−3 mol g−1, which was higher than that of a series of adsorbents reported in previousliterature. The interaction mechanism between ZIF-8/yeast composites and Eu(III) was primarily revealed by electrostatic attraction, cation exchange and surface complexation. According to the research, the ZIF-8/yeast is considered a preferable adsorbent for the highly efficient purification and elimination of trivalent lanthanides from radioactive wastewater. [ABSTRACT FROM AUTHOR]

The construction of 3D porous structures and metamaterials (MMs) is the most promising approaches to achieve broadband electromagnetic wave (EMW) absorption. However, it is still a huge challenge to achieve multispectral ultra‐broadband EMW absorption properties compatible with low‐frequency band (L‐ and S‐band) due to its ultralong wavelength and strong bypass capability. Herein, magnetic–dielectric synergistic gradient MMs (MDSGM) consisting of oriented flaky carbonyl iron (FCI) film and periodical RGO/CNT/CNF aerogel (GTFA) array are demonstrated. Benefiting from the synergistic effect of strong magnetic–dielectric loss, structural loss, and excellent impedance matching, MDSGM harvests an exciting multispectral ultra‐broadband EMW absorption performance with a remarkable effective absorption bandwidth covering the whole measured frequency of 1–40, 50–110 GHz, and 0.1–2.0 THz for the first time. The minimum RL (RLmin) reaches −40.24 dB and average RL is up to −19.3 dB (98.8% EMW being absorbed) in microwave band. Moreover, this multispectral ultra‐broadband EMW absorption property is less affected by the incident angle. This work pioneered realization of multispectral ultra‐broadband EMW absorption compatible with low‐frequency, which provides a great thrust for the development of stealth technology in the upcoming smart era. [ABSTRACT FROM AUTHOR]

Heterointerface engineering is an attractive approach to modulating electromagnetic (EM) parameters and EM wave absorption performance. However, the weak interfacial interactions and poor impedance matching would lead to unsatisfactory EM absorption performance due to the limitation of the construction materials and design strategies. Herein, multilevel heterointerface engineering is proposed by in situ growing nanosheet-like NiCoO 2 and selenides with abundant interface structures on 3D-printed graphene aerogel (GA) skeletons, which strengthens the interfacial effect and improves the dielectric polarization loss. Benefiting from the features of substantially enhanced polarization loss and optimized impedance matching, the graphene/S-NiCoO 2 /selenides (G/S-NCO/Se) have achieved brilliant EM wave absorption performance with a strong reflection loss (RL) value of -60.7 dB and a broad effective absorption bandwidth (EAB) of 8 GHz, which is about six times greater than that of the graphene aerogel (-9.8 dB). Moreover, it is further confirmed by charge density differences and off-axis electron holography that a large amount of polarized charge accumulates at the interface, leading to significant polarization relaxation behaviors. This work provides a deep understanding of the effect of a multilevel heterogeneous interface on dielectric polarization loss, which injects a fresh and infinite vitality for designing high-efficiency EM wave absorbers.