Modulation of magnetodielectric equilibrium in porous biochar embedded with MOF-derived CeO2/Fe3O4 for excellent electromagnetic absorption and anti-microbial properties

The design of electromagnetic wave absorbing composites is an important approach for achieving radar stealth and anti-electromagnetic interference. However, the bacterial metabolic byproducts can corrode the components and micro-structures of absorbers as employed in a bacteria-rich environment, thereby progressively reducing their absorption properties. To address this problem, herein the biomass-derived porous carbon decorated with magnetic Fe₃O₄ and dielectric CeO₂ deriving from Ce-UIO-66 was obtained via co-solvothermal and calcination route. The thin-walled porous biological carbon can not only dissipate incident microwave by scattering effect, but also act as carrier to provide sufficient dielectric properties. The co-modification of CeO₂ and Fe₃O₄ with varied doping of Fe³⁺ promotes the magnetodielectric equilibrium for better impedance matching, which can couple multi-ply mechanisms of dielectric polarization, conduction dissipation, eddy-current and natural resonance loss to achieve outstanding microwave absorption. The maximum RL value reaches -60.60 dB at 15.69 GHz for 2.00 mm thickness and the widest EAB is 6.41 GHz for only 2.19 mm thickness, the simulation proves the reduction of radar cross section within wide range of incident angles as well. Moreover, the ROS generated from abundant oxygen vacancies in absorber can realize high anti-bacterial efficiencies of 82.70% and 91.60% against S. aureus and E. coli, respectively. Hence, the work proposes a novel insight to design antibacterial electromagnetic absorbers for application in complex bacterial environment.