Optimization of electromagnetic wave absorption properties of CoNi/MoSe2 composites with 3D flower-like by controlling the Co/Ni molar ratio

Developing composite materials with a rational composition structure has been a critical strategy to obtain superior electromagnetic (EM) wave absorption materials. CoNi/MoSe 2 composites were synthesized by a two-step method in this work. Firstly, the flower-like MoSe 2 was synthesized by hydrothermal method , and then the CoNi alloy was loaded on the MoSe 2 surface by an electroless plating method. It is worth noting that in this paper, PdCl 2 was not used for activation during the electroless plating process, and the flower-like structure of MoSe 2 was not destroyed. In order to investigate the effect of different Co/Ni molar ratios on the absorption performance of the CoNi/MoSe 2 composites, three samples with Co to Ni molar ratios of 1:3, 1:1, 3:1 and two other samples with only one metal (Ni or Co) were prepared. The analysis results show that the minimum reflection loss(RL) value of Ni/MoSe 2 is −18.01 dB and the maximum effective absorption bandwidth(EAB) of Co/MoSe 2 is 2.16 GHz. In comparison, the CoNi/MoSe 2 composite exhibits the best EM wave absorption performance when the Co/Ni ratio is 1:3, and the minimum RL can reach −48.6 dB at a matching thickness of only 1.8 mm. And when the matching thickness is 1.4 mm, the broadest EAB is 3.76 GHz. Therefore, this work provides a new research idea for the design of broadband and efficient EM wave absorbers.