Spatial Confinement Growth Enabling MoS@Hollow Mesoporous Carbon Spheres Microspheres with Enhanced Microwave Absorption and Corrosion Resistance.

The complex electromagnetic applications in harsh corrosive environments urgently require research into multifunctional microwave absorption (MA) materials. The core-shell structure is an effective strategy to prepare multifunctional MA materials by efficiently combining the advantages of each component. Nevertheless, it remains a tough challenge to elucidate the effect of the binding positions of each component in MA materials on the comprehensive electromagnetic performance. Herein, two types of core-shell structured composites based on hollow mesoporous carbon spheres (HMCS), HMCS@MoS and MoS@HMCS, were prepared via synergistic etch growth and spatial confinement growth strategies, respectively. Compared with HMCS, HMCS@MoS severely destroys the connection of HMCS, therefore resulting in impedance mismatching. Comparatively, the growth of MoS within the HMCS reduces the disruption of the HMCS connection, enabling MoS@HMCS with enhanced dielectric loss while optimizing the impedance matching, and therefore, it yields an optimal reflection loss of -46.91 dB at 2 mm and an effective bandwidth of 5.78 GHz at 2.4 mm mixed with polydimethylsiloxane (PDMS). In addition, the combinations of the spatial confinement effect of HMCS, corrosion resistance of MoS, and chemical stability of PDMS resulted in minimal changes in the MA performance of MoS@HMCS/PDMS after soaking in acidic and alkaline solutions for 14 days, proving an excellent corrosion resistance property. This inspiring work proposes an effective spatial confinement growth strategy to optimize the impedance matching and further tailor the multifunction for dielectric loss dominated MA materials.