Highly conductive mesoporous hierarchical carbon hollow fibers fabricated via confinement of TiO2 coating by ALD

Abstract

AbstractA polysulfone (PSF) hollow fiber composed of interconnected nanofibers within its wall was employed as a template to deposit with a layer of TiO2 by atomic layer deposition. Direct nitridation of the TiO2‐coated PSF hollow fiber at 800 and 1000°C was conducted, and a new hierarchical structure of TiOxN1−x and TiN@nitrogen‐doped carbon hollow fibers, respectively, was formed. The PSF fiber served as the source of carbon and was directly transformed to a nitrogen‐doped carbon fiber because the shape change was confined by the TiO2 coating. In the meantime, TiOxN1−x or TiN was formed after the nitridation of TiO2. X‐ray photoelectron spectrometric analysis indicated that there was no chemical bonding between the nitridized coating and the carbon nanofibers. It implies that the nitridation of TiO2 and carbonization of PSF proceed independently and simultaneously in the nitridation process. Raman spectroscopic analysis also confirmed the formation of graphitic lattice and Ti–N bonding. Electrical measurement indicated that both fibers were highly conductive, with the electrical resistivity in the order of 10−5 Ω m, which is lower than those of amorphous carbon and graphite along the direction perpendicular to the basal plane.