Construction of 1D porous MOF-derived ZnO/C fibers anchored by 0D cobalt nanoparticles for enhanced microwave absorption and thermal conductivity

Abstract

As to most traditional microwave-absorbing materials, weak thermal conductivity and narrow absorption bandwidth have greatly limited their practical applications. In this work, a novel synthesis strategy was put forward to construct the porous one-dimensional (1D) ZnO/C fibers anchored by zero-dimensional (0D) cobalt nanoparticles (Co–ZnO/C) via a synergistic approach combining electrospinning, seed-assisted growth of ZnCo bimetal-organic frameworks (MOFs), and carbonization processes. Changing metal cobalt ion ratios in the fibers can effectively adjust the graphitization degree and electromagnetic parameters, and then correspondingly enhance the microwave absorption performance. Further, reduced cobalt nanoparticles significantly amplify interfacial polarization and magnetic loss, while the hierarchical porous structure optimizes impedance matching. Consequently, increasing the cobalt contents leads to an improvement in RL_min from −50.83 dB to −63.42 dB, albeit with a slight decrease in the EAB_max from 7.28 GHz (10.72–18.00 GHz) at 2.50 mm to 7.04 GHz (9.12–16.16 GHz) at 2.90 mm. Excessive addition of cobalt ion can also result in a decrease in microwave absorption performance. Specific porous 1D structure extends the electron transport path and enhances thermal conductivity of the Co–ZnO/C composites. The corresponding thermal conductivity reaches 0.318 W m⁻¹ K⁻¹, which is 40 % higher than that of pure epoxy resin. The superior electromagnetic wave absorption performance, coupled with the elevated thermal conductivity, renders the as-synthesized Co–ZnO/C composites highly promising for application in the design and manufacture of next-generation wireless communication equipment and high power devices.