Controllable construction of terrace-like biomass-derived porous carbon for high-efficiency microwave absorption

The development of high-performance microwave-absorbing materials from renewable resources is a crucial pathway toward achieving green electromagnetic protection. In this work, biomass-derived porous carbon with a terrace-like pore structure was successfully fabricated from potato via a synergistic pyrolysis-chemical activation strategy. The influence of KOH concentration on microstructural evolution and microwave absorption performance was systematically investigated. The results demonstrate that at an optimal KOH concentration of 2 mol/L, the material exhibits a honeycomb-like architecture composed of terrace‑like pores, exhibiting excellent microwave absorption performance: a minimum reflection loss of −64.97 dB at a matching thickness of 2.1 mm and an effective absorption bandwidth of 6.82 GHz (11.18–18.00 GHz) at a thickness of 2.53 mm. The excellent performance originates from the synergistic effects of conductive loss provided by the terrace-like conductive network, polarization relaxation loss induced by multi-level interfaces and broadband impedance matching enabled by the gradient pore structure. This study offers a feasible preparation strategy and theoretical support for synthesizing lightweight, high-efficiency and broadband microwave-absorbing materials from agricultural waste.