Electrospun polyacrylonitrile/β-cyclodextrin based porous carbon nanofiber self-supporting electrode for capacitive deionization

With beta-cyclodextrin (beta-CD) as an additive, porous carbon nanofibers (PCNF beta-CD) with good graphitization have been fabricated by electrospinning polyacrylonitrile/beta-cyclodextrin (PAN/(beta-CD)) pristine fibers followed by preoxidation and carbonization. The nanopores were formed by the dehydration and decomposition of beta-CD at high temperature. The specific surface area and pore density can be conveniently tuned by adding different amounts of beta-CD in the precursor solution. The resultant porous carbon fibers were characterized by scanning electron microscopy, N-2 adsorption/desorption analysis and fourier transform infrared spectroscopy. Raman analysis indicates that the graphitic network of the porous carbon is improved with the addition of beta-CD. With the porous carbon fiber web as a selfstanding electrode, the electrochemical properties of the electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. PCNF beta-CD were employed as active electrodes for capacitive deionization (CDI). The optimal desalination amount of 11.65 mg g(-1) was achieved on the PCNF beta-CD fabricated with the PAN/(beta-CD) ratio of 1 : 0.8, which is significantly higher than that of pure PAN-based carbon nanofibers. Multiple charge-discharge cycling of the CDI cell was tested and the regeneration of the electrode was demonstrated.