Bimetallic MOF@wood-derived hierarchical porous carbon composites for efficient microwave absorption

Biomass-based porous carbon composites have received widespread attention in microwave absorption field due to sustainable sources, unique micro-nano structure, low cost. Nevertheless, it is still a huge challenge to construct biomass-derived microwave absorbers with reasonable structure and multi-component magnetic/dielectric structures in order to satisfy the conditions of advanced electromagnetic wave absorption materials. Herein, CoNi-metal-organic framework (MOF) was grown in-situ on the wood, and CoNi@wood-derived porous carbon composites (WNC) were fabricated by in situ annealing at different temperatures under a nitrogen atmosphere. When the pyrolysis temperature was 700 °C and the loading amount was 30 wt%, the optimal minimum reflection loss of WNC composites could reach −25.96 dB at 17.98 GHz with a thickness of 1.8 mm. The outstanding microwave absorbing capacity is ascribed to the interfacial polarization, conduction loss, dipolar polarization, magnetic loss, and multiple reflections. This research paves a new preparation method for excellent microwave absorption materials.