Nitrogen plasma modification of viscose-based activated carbon fibers

Viscose-based activated carbon fibers (VACFs) were treated by a dielectric-barrier discharge plasma at different conditions. Nitrogen was used as the feed gas to create nitrogen radicals. The textural characteristics were analyzed by SEM, BET and XRD. The surface chemical functional groups were analyzed by XPS. The results show that after nitrogen plasma modification (NPM), the external surface of the VACFs was etched and became rougher, the surface area and pore volume decreased, the average micropore width barely changed, the PSD of the VACF became narrower and the graphitic crystallites of VACF had been destroyed slightly. XPS revealed that NPM could remarkably change the distribution of the oxygen functional groups on the VACFs surface and there were more nitrogen atoms incorporated into the aromatic ring. A tentative explanation for the modification process is proposed.