Co/Er2O3/C ternary nanocomposites derived from cobalt/erbium Prussian blue analogs for efficient microwave absorption

Abstract

This study presents the synthesis of Er[Co(CN)₆], a Prussian blue analog (ErCo-PBA) with varied morphology, fabricated by modulating the solvent ratio between C₂H₆O and H₂O. This approach leverages the solubility characteristics of K₃[Co(CN)₆] and the consequential influence of C₂H₆O on the crystal growth. When the solvent ratios are 1:8, 8:1, and 1:1, the resulting ErCo-PBA precursors nanorods, irregular particles, and spindle-shaped particles, respectively. After annealing, these precursors in an Ar environment allowed the Co/Er₂O₃/C derivatives to retain the morphology of the precursor well. Electromagnetic parameters testing revealed that Co/Er₂O₃/C-1 exhibits superior electromagnetic wave-absorbing (EMWA) performance among the synthesized derivatives with an effective absorption bandwidth of 5.1 GHz at 1.85 mm and a minimum reflection loss of −56.7 dB at 2.9 mm. The incorporation of Er₂O₃ is an effective method for adjusting and optimizing the electromagnetic parameters of materials, thereby enhancing the EMWA performance of Co/Er₂O₃/C composite. This study highlights the potential of rare-earth oxide/Co/C composites, synthesized through direct annealing rare-earth metal–organic frameworks, as an absorber and are promising candidate to achieve high-efficiency electromagnetic wave absorption.