Quanfen Guo

Structural–functional integrated polymer fibers with exciting properties are increasingly important for next-generation technologies. Herein, we report the structural–functional integrated graphene-skinned aramid fiber (GRAF) featuring high conductivity, high strength, and light weight, which is weaved for efficient electromagnetic interference (EMI) shielding. Graphene was self-assembled onto the surface of aramid fibers through a dip-coating strategy using an aramid polyanion (APA) as the binder and the etchant. The molecular dynamics (MD) simulation results show that the binding energy of the APA-modified aramid chain and graphene (1.3 J/m2) is superior to that of the aramid chain and graphene (0.2 J/m2). The APA has a higher surface energy (55.2 mJ/m2) and can etch the fiber surface, forming grooves, which enables effective adsorption and self-assembly of graphene onto the fiber surface. The GRAF exhibits a high conductivity of 1062.04 ± 116.78 S/m, along with excellent strength (4.66 ± 0.16 GPa) and modulus (106.33 ± 8.21 GPa), outperforming most reported conductive composite fibers (e.g., natural fibers, polymer-based fibers, inorganic fibers, etc.). The weaved functional fabric using the structural–functional integrated GRAF shows an EMI shielding efficiency (SE) of up to 67.86 dB in the X-band and can rapidly heat up to 200 °C within 40 s at 12 V voltage. In addition, the GRAF fabric can maintain its electrical conductivity after a long-term washing, showing excellent washing resistance. This study demonstrates an effective method to fabricate structural–functional integrated materials and shows the promise of carbonene fibers for EMI shielding.

Nitrogen-doped graphene aerogel microspheres (rGNAMs) are prepared by electrospraying the graphene oxide dispersion with pyrrole and an oxidation agent and then subjecting it to freeze-drying and thermal annealing. The rGNAMs possess a high surface area, an interconnected pore structure, and uniform N doping. The Pt nanoparticles (Pt NPs) are loaded into rGNAMs through a hydrothermal reduction reaction to obtain the Pt/rGNAM composite catalyst for methanol electrooxidation. The N-doping structure of rGNAMs can improve the loading ratio of Pt on the carrier, decrease the dimension of Pt NPs, homogenize the dispersion of Pt NPs, and increase the content of Pt(111) crystal planes. Consequently, the oxidation activity of Pt/rGNAMs to methanol is improved compared to that without N doping. The optimized Pt/rGNAM composites used as anode electrocatalysts display a remarkable mass activity of 840.11 mA mg–1 for methanol electrooxidation, which is about 4.9, 2.9, and 2.7 times higher than that of Pt/C, Pt/rGNAB (Pt/N-doped graphene aerogel bulk), and Pt/rGNAS (Pt/N-doped graphene aerogel millimeter spheres), respectively. Moreover, the Pt/rGNAMs also show superior long-term electrocatalytic stability. This work develops a new Pt/rGNAMs composite for potential application in fuel cells.