Furan and Pyran Functional Groups Driven the Surface of Nitrogen‐Doped Nanofiber Sponges

Abstract Highly surface oxidized, nitrogen‐doped, and nitrogen functionalized carbon nanotube sponge (N‐CFS) were produced at 1020 °C using two sprayers approach in an aerosol‐assisted chemical vapor deposition (AACVD) experiment. The structure of N‐CFS consisted of entangled and corrugated carbon nanofibers of ∼200 nm diameter, also showing junctions and knots. TEM characterizations revealed that the carbon nanofiber exhibits stacked graphitic layers in a transversal way with positive curvature. Superficial chemical analysis by XPS showed that the N‐CFSs contain an atomic concentration of oxygen and nitrogen of 9.2% and 2.9%, respectively. The high‐resolution XPS scans deconvolution‐analysis revealed high percentages for C−O bonds, pyrrolic nitrogen doping, NH₃ functionalization, and Si−C interactions. The cyclic voltammetry measurements did not display a redox process despite the high oxygen concentration at the surface. Hydrophobic functional groups containing C−O bonds do not participate in a redox process (furan, pyran, epoxy, methoxy, ethoxy, among others) could mostly determine the electroactivity of N‐CFS. Based on density functional theory calculations, we determine that the furans transfer a high amount of electron and promote a positive curvature in thin carbon nanotubes. Graphitic materials with furans, pyrans, and epoxy functional groups could be used as an anode in lithium‐ion batteries.