Metal Valence State Modulation Strategy to Design Core@shell Hollow Carbon Microspheres@MoSe₂/MoO_x Multicomponent Composites for Anti‐Corrosion and Microwave Absorption

Abstract

The exploitation of multicomponent composites (MCCs) has become the main pathway for obtaining advanced microwave absorption materials (MAMs). Herein, a metal valence state modulation strategy is proposed to tune the electromagnetic (EM) parameters and improve microwave absorption performances. Core@shell hollow carbon microspheres@MoSe2 and hollow carbon microspheres@MoSe2/MoOx MCCs with various mixed‐valence states content are well‐designed and produced by a simple hydrothermal reaction or/and heat treatment process. The results reveal that the thermal treatment of hollow carbon microspheres@MoSe2 in Ar and Ar/H2 leads to the in situ formation of MoOx and multivalence state, respectively, and the enhanced content of Mo4+ in the designed MCCs greatly boosts their impedance matching characteristics, polarization, and conduction loss capacities, which lead to their evidently improved EM wave absorption properties. Amongst, the as‐prepared hollow carbon microspheres@MoSe2/MoOx MCCs achieve an effective absorption bandwidth of 5.80 GHz under a matching thickness of 1.97 mm and minimum reflection loss of −21.49 dB. Therefore, this work offers a simple and universal method to fabricate core@shell hollow carbon microspheres@MoSe2/MoOx MCCs, and a novel and feasible metal valence state modulation strategy is proposed to develop high‐efficiency MAMs.

Ultraflexible Ultrathin 3D/1D Hierarchical Interpenetrating Ni-MOF/CNT Buckypaper Composites: Microstructures and Microwave Absorption Properties

“…It is observed in Figure 4 that the tan δ ε values of BP-9-10/3, BP-9-10/5, and Conductivity loss and relaxation loss are the key factors causing dielectric loss in MAMs. 18,60,61 ε″ denotes the attenuation of energy, consisting of conduction losses and relaxation losses. 63 The free charge migrates, jumps, and transports in the Ni-MOF/CNT BP network, and the charge collides with each other to produce conductivity loss.…”

“…Moreover, tan δ ε and tan δ μ reveal the dielectric loss and magnetic loss capacity of the MAMs. It is observed in Figure 4 that the tan δ ε values of BP-9-10/3, BP-9-10/5, and BP-9-10/7 are larger than the tan δ μ values throughout the 2− 18 GHz band, and this result indicates the dominance of dielectric loss in the BPs.Conductivity loss and relaxation loss are the key factors causing dielectric loss in MAMs 18,60,61. ε″ denotes the attenuation of energy, consisting of conduction losses and relaxation losses 63.…”