Iron-encapsulated CNTs on carbon fiber with high-performance EMI shielding and electrocatalytic activity

Although carbon fibers have been broadly used as electromagnetic shields, it is still a challenge to achieve high-efficiency shielding performances with tunable reflection/absorption mechanism. Herein, magnetic metal–encapsulated carbon nanotubes (CNTs) grown on carbon fibers are fabricated via a modified chemical vapor deposition procedure, whose electrical conductivity and electromagnetic shielding abilities can be effectively regulated by control of the metal ion constituent. The magnetic metal–encapsulated CNT bunches are densely grown on the surface of carbon fibers. In comparison with pristine carbon fibers possessing reflection-dominant shielding mechanism, the decoration of magnetic metal–encapsulated CNTs can effectively regulate reflection/absorption mechanism and is beneficial for the improvement of absorption. Off-axis electron holograms were applied to investigate electromagnetic absorption mechanism consisting of magnetic resonance (magnetic coupling interaction) and conductive loss (charge density distribution). CNTs grown on carbon fibers exhibit enhanced electromagnetic interference (EMI) shielding abilities with total shielding effectiveness values of more than 40 dB (blocking 99.99% EM waves). Furthermore, it also shows boosted oxygen evolution reaction performance with an overpotential of 344 mV and desirable stability, which was attributed to the improved conductivity and effective composite structure design.Graphical abstractMagnetic metal–encapsulated CNTs on carbon fibers exhibit defunction performances of the enhanced EMI shielding and oxygen evolution reaction