Synthesis of NiCo2-0.5xCr2O3@C nanoparticles based on hydroxide with the heterogeneous interface for excellent electromagnetic wave absorption properties

Abstract A great deal of work has been implemented to achieve perfect control of the composition and structure of porous nanomaterials, which can be utilized as a high-efficiency and low-thickness electromagnetic wave (EMW) absorber. Here, a novel and lightweight EMW absorbing material consisting of NiCo alloy and Cr oxide supported on porous carbon was prepared through thermal decomposition and partial reduction of hydroxide. The effect of the content of Cr(NO3)3•9H2O on electromagnetic properties was systematically studied. It was found that the NiCo2-0.5xCr2O3@C composites could achieve an excellent reflection loss (RL) of −52.71 dB at 1.6 mm and an effective absorption bandwidth (EAB) of 5.28 GHz at 1.89 mm via introducing additional NiCo2–Cr2O3 into the porous carbon composite. The results suggest that the synergistic effect between the appropriate proportions of Cr2O3, NiCo alloy and porous carbon optimizes the impedance matching and greatly improves the absorption performance. The enhanced EMW absorption performance of NiCo2-0.5xCr2O3@C confirms that this work provides a favorable strategy for other carbon-based absorbers.