Waste polypropylene-derived TiO2/Co-CNTs composites with broadband electromagnetic wave absorption

Advanced carbon-based electromagnetic wave (EMW) absorption materials are essential for addressing the growing issue of electromagnetic interference and pollution, while the limited preparation methods of these materials have hindered their practical applications. Herein, waste polypropylene-derived carbon-based composite (TiO 2 /Co-CNTs) microwave absorption materials were prepared involving catalytic pyrolysis and chemical vapor deposition techniques. By strategically designing multiple interface structures incorporating magnetic components and supported catalysts, the electromagnetic parameters of the absorber can be optimized to achieve varying attenuation properties. Particularly, the composite material achieves a minimum reflection loss of −50.2 dB at 15.44 GHz at a low matching thickness of 1.6 mm, and a broad effective absorption bandwidth of ∼5 GHz at 1.7 mm. Simulations of surface current density further reveal that a more uniform and continuous current distribution is pivotal for excellent impedance matching and provides supplementary support for its improved electromagnetic coupling behavior. This work establishes a novel methodology for value-added utilization of waste plastics and offers a promising design concept for broadband and lightweight carbon-based EMW absorption materials.