Phase-incorporation-induced electromagnetic coupling of NFS@1T/2H–MoS₂ for enhanced microwave absorption

Herein, we propose a combination strategy to induce robust room-temperature electromagnetic coupling in non-magnetic MoS₂ semiconductor (2H–MoS₂). The introduction of ascorbic acid (AA) is intended to introduce sulfur vacancies (sv) in the process of 2H–MoS₂ nano-sheet shells coating on the surface of three-dimensional (3D) matrix. It promotes the transformation of local lattice (2H–MoS₂) into metal phase (1T-MoS₂). The transformed 1T-MoS₂ phase improves the conductivity (σ) of the composite by 1.48 times. Due to the Mo⁴⁺4d energy state within the bandgap, the exchange interaction between the sv and the Mo⁴⁺4d bandgap state produces a robust intrinsic electromagnetic response of more than 1.2 emu/g. Density functional theory (DFT) calculations are used to analyze the above results, and a novel electromagnetic-coupling-enhanced microwave absorption mechanism is proposed. The results indicates that microwave absorption performance can be effectively improved by the phase-incorporation effect. The minimum reflection loss (RL_min) reaches −53.1 dB (1.7 mm) and the adjustable effective absorption bandwidth (EAB) covers 14.5 GHz (3.5–18 GHz) at the various matching thicknesses. This work might shed light on a new possibility of manipulating electromagnetic interaction to promote microwave absorption.