Polydopamine-derived nitrogen-doped carbon coupled with MoSe2 nanosheets composites toward high-efficiency electromagnetic wave absorption

Molybdenum selenide (MoSe2) with the diverse crystal structures and unique electronic characteristics were restricted in field of the electromagnetic wave (EMW) absorbing (EMWA) owing to the poor electrical conductivity and easy agglomeration. Herein, a series of N-doped carbon (NC) coupled with MoSe2 nanosheets composites were synthesized via a brief selenization process of the self-polymerized Mo-polydopamine precursor. The as-prepared MoSe2/NC composites with good dispersibility exhibited the shape of ball-flower-like with a diameter ranging from 400 to 900 nm. Significantly, the electromagnetic parameters, the electrical conductivity, and N-doped defect rate could be effectively adjusted by varying the selenization temperature. As the temperature increased, the EMWA property of MoSe2/NC composites revealed a trend of first increasing and then decreasing. At 800 °C, the MoSe2/NC composites showed a minimal reflections loss value of −50.56 dB at 2.53 mm and covered a maximum effective absorption band value of 5.76 GHz at 2.0 mm with a filling ratio of 30 wt%. The enhanced EMWA performance stemmed from reinforced conductive loss, enriched polarization relaxation processes, optimized impedance matching, and porous characteristics. Furthermore, the radar cross section simulation results confirmed the MoSe2/NC composites coatings possessed superb EMWA capacity. This work provided a straightforward approach for designing highly efficient MoSe2-based EMW absorbers.