Single-atom Zn confined in hierarchical hollow microstructure as an acid/base-resistant microwave absorption materials

Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme environments. Herein, we demonstrate the successful synthesis of the N-doped porous carbon (NC) material with hierarchical pore structure by the spray pyrolysis method. The large specific surface area (S_BET = 707.53 m²·g⁻¹) of materials enables multiple scattering of incident electromagnetic waves, and N doping greatly enhances the electrical conductivity of the material. Notably, single-atom Zn can adjust the local electronic structure of adjacent sites such as carbon and nitrogen atoms, induce the center of polarization, and thus change the dielectric and electronic properties of the host material. The porous carbon coating of single-atom Zn avoids the deterioration of electromagnetic parameters caused by the accumulation of magnetic particles under high-temperature pyrolysis. At the same time, they can also be used in various complex environments, such as acidic and basic environments. Ultimately, NC-1000, with high surface area, low density, and good chemical stability, obtained a minimum reflection loss (RL_min) of −50.5 dB and an effective absorption bandwidth (EAB) exceeding 5.1 GHz at the thickness of 1.9 mm. After soaking in the strong acid and base solution, the electromagnetic wave absorption performance of the material decreased by < 15%. Widely available raw materials and a simple preparation scheme are expected to expedite industrial mass production for this novel type of materials.