Vacancies-engineered and heteroatoms-regulated N-doped porous carbon aerogel for ultrahigh microwave absorption

Abstract

Carbon materials are expected to be the promising candidates for lightweight absorbers, however, structure design and composition control still possess a formidable challenge. Herein, we develop a controllable method to synthesize vacancies-engineered and heteroatoms-regulated N-doped porous carbon aerogel (NPCA), involving the formation of the gelatin of rigiditied organic polymer aerogel via a Schiff-base reaction and a subsequent pyrolysis process. By increasing the pyrolysis temperature, the proportion of N heteroatoms decreases while more vacancies can be generated, resulting in adjusted microwave absorption performance. As microwave absorber, the NPCA exhibits ultrahigh absorption performance because of matched impedance, interconnected conductive network and multiple scattering. Balancing the conduction loss and dipolar/interfacial polarization, an optimal reflection loss of −61.7 dB is achieved at 2.6 mm and the effective bandwidth is as wide as 11.7 GHz when the thickness ranges from 1 mm to 4 mm for NPCA-800. Considering the outstanding performance and precise controllability, we believe that the synthesized carbon aerogel can be used as lightweight microwave absorbers and this strategy provides the most cutting-edge topic for the fabrication of carbon aerogel derived from organic polymer aerogel with tunable composition/structure.