Metal Valence State Modulation Strategy to Design Core@shell Hollow Carbon Microspheres@MoSe2/MoOx 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@MoSe 2 and hollow carbon microspheres@MoSe 2 /MoO x 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@MoSe 2 in Ar and Ar/H 2 leads to the in situ formation of MoO x and multivalence state, respectively, and the enhanced content of Mo 4+ 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@MoSe 2 /MoO x 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@MoSe 2 /MoO x MCCs, and a novel and feasible metal valence state modulation strategy is proposed to develop high‐efficiency MAMs.