Carbon　materials　have　aroused　wide　attention　in　the　field　of　electromagnetic　wave　absorption　because　of　their　advantages　of　good　electrical　conductivity,　low　density　and　adjustable　structure.　To　obtain　enhanced　performance　of　electromagnetic　wave　absorption,　the　elaborate　design　of　structures　for　carbon　materials　has　become　essential.　In　this　work,　the　nitrogen-doped　and　large　diameter　carbon　nanotubes　modified　with　cobalt　nanoparticles　(M-Co/C-CNTs)　composites　were　successfully　prepared　by　adsorption　and　carbonization　of　the　gases　generated　by　organic　matter　pyrolysis.　It　is　concluded　that　the　enhanced　conduction　loss　and　polarization　loss　are　attributed　to　the　interfacial　electronic　engineering　induced　by　the　sensibly　loaded　cobalt　nanoparticles　and　nitrogen　doping.　As　a　result,　the　samples　achieved　a　broad　effective　absorption　bandwidth　of　4.56　GHz,　and　a　strong　reflection　loss　of　−52.2　dB　with　a　thin　thickness　of　2.1　mm.　This　work　proposes　a　tailored　way　to　fabricate　the　large　diameter　carbon　nanotube　composites　and　enhance　electromagnetic　wave　absorption　through　novel　structural　modulation.　©　2022　Elsevier　Inc.