Carboxymethyl cellulose/tea polyphenol/polypyrrole-derived carbon aerogel for electromagnetic wave absorption

In recent years, the fabrication of lightweight porous carbon aerogels from biomass precursors has attracted considerable attention in the field of electromagnetic wave absorption. Herein, novel Fe₃O₄/FeN/N porous carbon aerogels were successfully synthesized using sodium carboxymethyl cellulose as the carbon source, with metal-phenolic networks constructed through the coordination of tea polyphenols and Fe³⁺. These networks not only enable homogeneous dispersion of polypyrrole but also mitigate the shrinkage of carbon frameworks during high-temperature pyrolysis, thereby maintaining the structural integrity of the aerogel products. The as-prepared carbon aerogels possess a hierarchical porous structure and well-developed conductive networks. Electromagnetic parameter tests revealed that the materials achieved a minimum reflection loss of -58.4 dB at a matching thickness of 3.1 mm, together with a broad effective absorption bandwidth of 5.3 GHz at a thickness of 2.1 mm. This work offers an innovative strategy for the green and efficient utilization of cellulose-based materials and demonstrates their potential for developing lightweight, high-performance electromagnetic wave absorbers.