MOFs-derived 3D flower-like Y2O3/C microspheres with efficient electromagnetic wave absorption properties

Abstract

Y2O3 has emerged as a promising material for electromagnetic wave (EMW) absorption due to its excellent dielectric properties. However, the inherent insulating nature and single loss mechanism limit its absorption performance. Research on the microstructure modulation and component regulation of Y2O3-based absorbers remains relatively unexplored. In this work, Y2O3/C composites with flower-like architectures were synthesized for the first time via a metal-organic framework (MOFs) templating method. The effects of pyrolysis temperature on the microstructure, phase composition, and EMW absorption performance of the Y2O3/C composites were systematically investigated. At a pyrolysis temperature of 800 °C, the flower-like Y2O3/C microsphere exhibited optimal EMW absorption performance. The minimum reflection loss (RL) of pristine Y2O3 was only −4.75 dB, while the Y2O3/C composite achieved a minimum RL of −51.77 dB and a maximum effective absorption bandwidth of 4.32 GHz. Moreover, by simply adjusting the matching thickness, the optimal sample exhibited strong absorption (RL < −30 dB) over a wide frequency range of 4–18 GHz. The incorporation of carbon effectively neutralized the insulating nature of Y2O3, thereby optimizing the impedance matching. The synergistic effects of multiple loss mechanisms, including polarization loss, resistance loss, and interfacial polarization, facilitated substantial EMW attenuation. This study provides a promising strategy for the design and fabrication of high-performance rare-earth oxide EMW absorbers with tunable morphologies and properties.