Abstract: Carbon materials are thought of as the ideal microwave absorbers owing to their tunable microstructures, low densities, and exceptional properties. In this work, a facile template-assisted strategy was proposed to produce mesoporous carbon hollow nanospheres (HNSs) through continuous polymerization, heat treatment, and HF etching processes. Different mesopores and aperture sizes of mesoporous carbon HNSs could be produced by regulating the content of silicon source, which resulted in the tunable electromagnetic (EM) parameters and excellent EM wave absorption properties (EMWAPs). Moreover, a simple and effective N-doped strategy was presented to selectively produce mesoporous N-doped carbon HNSs with different N-doped contents. The acquired outcomes demonstrated that the designed multi-faceted optimization strategy yielded outstanding EMWAPs of mesoporous N-doped carbon HNSs including low density, high EM wave attenuation capacity, broad effective absorption bandwidth (EAB), and good corrosion resistance. Especially, the acquired mesoporous N-doped carbon HNSs presented a remarkable EAB of 7 GHz and an impressive minimum reflection loss of -51.39 dB at a thickness of merely 1.97 mm. Consequently, this research provided a combined microstructural optimization and heteroatom doping strategy to develop mesoporous N-doped carbon HNSs for EM wave absorption.

Key words: Mesoporous N-doped carbon hollow nanospheres, Microstructural optimization, Heteroatom doping, Broad absorption bandwidth, Microwave absorption