Metal–organic framework derivatives with gradient structures via multidimensional assembly engineering for tunable efficient microwave absorption

Abstract

Developing carbon-based composites with ideal microstructure and component morphology is crucial for optimizing electromagnetic parameters and thus obtaining high-performance electromagnetic wave absorbers. However, there are currently significant challenges to the generalized design of precise assembly regulation strategies for different dimensional carbon-based structural materials and the in-depth understanding of the association model between assembly structures and attenuation mechanisms. In this study, two one-dimensional (1D) cobalt (Co)- containing metal–organic frameworks (MOFs) were employed as the initiating cores, and the epitaxial growth, solvent-assisted ligand exchange (SALE), and controlled pyrolysis strategies were ingeniously combined to innovatively construct 1D nanowires/rods assembled with zero-dimensional (0D) nanobubbles of nanowire/nanorod@bubble-C Co particles doped with carbon-based composites. Influenced by the variability of the aspect ratio of the overall 1D structure and the size and distribution of surface bubbles, different composites exhibit structurally differentiated dissipative response mechanisms and properties. Among them, nanowire@bubble-C exhibits significantly enhanced dielectric relaxation and magnetic loss, achieving strong absorption. Furthermore, nanorod@bubble-C has a balanced mechanism of conductive loss and dielectric relaxation, optimized structure matching and magnetic/dielectric synergy effect, and obtained excellent and effective absorption bandwidth. This study provides a useful reference for exploring the design of multidimensional assembled carbon-based materials and the effect of nanostructures on microwave absorption properties and mechanisms.