Metal Valence State Modulation Strategy to Design Core@shell Hollow Carbon Microspheres@MoSe/MoO Multicomponent Composites for Anti-Corrosion and Microwave Absorption.

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 and hollow carbon microspheres@MoSe/MoO 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 in Ar and Ar/H leads to the in situ formation of MoO and multivalence state, respectively, and the enhanced content of Mo 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/MoO 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/MoO MCCs, and a novel and feasible metal valence state modulation strategy is proposed to develop high-efficiency MAMs.