Construction of 0D/2D M/rGO@EuMOF multiscale heterostructures for integrated high-efficiency microwave absorption and corrosion protection

Developing multifunctional materials with integrated microwave absorption and corrosion resistance is crucial for expanding the practical application scope of functional materials in complex marine environments. In this work, a series of multiscale zero-dimensional/two-dimensional (0D/2D) heterostructure composites (denoted as MG@E) were successfully fabricated via a facile in-situ hydrothermal method. In this structural design, zero-dimensional europium-based metal–organic framework (EuMOF) microspheres are uniformly anchored on two-dimensional modified reduced graphene oxide (M/rGO) nanosheets, which effectively optimizes the impedance matching characteristic and improves the electromagnetic wave attenuation capacity of the composites. The excellent microwave absorption performance of MG@E composites originates from the synergistic effects of multiple loss mechanisms, including interfacial polarization at 0D/2D heterointerfaces, dipole polarization of MOF ligands, conductive loss, and magnetic dissipation. The optimized MG@E3 sample delivers a minimum reflection loss (RL) of −54.02 dB at a matching thickness of 2.1 mm, and a maximum effective absorption bandwidth (EAB) of 4.5 GHz at a thin thickness of 1.4 mm. Furthermore, the electrochemical test results demonstrate that MG@E composite coatings can significantly improve the corrosion resistance of Q235 steel. Specifically, the MG@E2 sample achieves a corrosion protection efficiency of 94.8% even after 21 days of immersion in 3.5 wt% NaCl solution. The improved anti-corrosion performance is mainly attributed to the synergistic barrier effect derived from the 0D EuMOF microspheres embedded in the 2D labyrinth-like structure of M/rGO, which inhibits the penetration of corrosive media. It is worth noting that the comprehensive performance of the composites is still restricted by material dosage and preparation conditions to a certain extent. This work provides a feasible and referential strategy for the rational design and preparation of high-performance microwave absorption materials with improved marine environmental adaptability and long-term service potential.