Trimetallic Prussian blue analogue derived FeCo/FeCoNi@NPC composites for highly efficient microwave absorption

Recently, Prussian blue analogues (PBA) have emerged as attractive precursors or templates for the construction of porous carbon-based microwave absorption (MA) materials because of their open framework, tunable components and mild synthesis conditions. Herein, for the first time, trimetallic FeCoNi-PBA nanocubes are introduced as precursors, and then a novel core-shell structured composites, in which FeCo and FeCoNi alloy nanoparticles are uniformly encapsulated in N-doped porous carbon (FeCo/[email protected]), are successfully synthesized via a pyrolysis process. Benefiting from the strong synergetic effects among multiple components (FeCo, FeCoNi alloys and N-doped carbon species) and the hierarchical porous structure, the absorber exhibits significantly enhanced MA performance in comparison with [email protected] and [email protected] derived from bimetallic PBAs. Impressively, the minimum reflection loss (RL) is up to −67 dB at 14.7 GHz with a thin thickness of 1.91 mm, and the corresponding effective absorption bandwidth (EAB) reaches 6.24 GHz, covering the whole Ku-band. When the thickness is 2.05 mm, the maximum EAB of 6.6 GHz can be obtained. In particular, the absorber can also achieve full absorption of X-band at 2.68 mm. More importantly, the multi-metallic PBA derivation strategy sheds new light on development of lightweight carbon-based absorbers with high performance, low cost and easy synthesis.