| dc.description | The objective of this thesis was to develop an electrospun polyacrylonitrile (PAN)-based
nanofiber that has unique properties as an electrode material. Stabilizing, carbonizing, and
chemical activation of these nanofibers can help to improve meso-porous carbon for the
application as carbon-based electrodes. The study includes two main parts.
In part I, nanofibers were electrospun under different electrospinning conditions, such as
applied voltage and the distance between the spinneret and the target, to determine the best
process conditions. Then, the PAN nanofibrous mats were stabilized in air, carbonized in inert
atmosphere (argon), and activated using a potassium hydroxide (KOH) chemical method. During
the chemical activation, carbonized nanofibers were immersed in an aqueous KOH solution.
In part II, the structure and morphology were studied using scanning electron microscopy
(SEM). The diameter of the nanofibers was measured and monitored as a function of the applied
voltage, distance between the spinneret and the target, and the chemical (KOH) treatment.
Porosity of carbon-based nanofibers has been studied by weighing the nanofibrous mat after
absorption of isopropanol. Porosity by chemical treatment improved from 60% to 90%, thus
providing a higher contact area, which is an important factor for electrodes. As a result of the
physical and chemical treatments, wettability of the electrospun nanofibers varied from
hydrophobicity with a contact angle of 150° to superhydrophilicity with a contact angle of 20°.
The electrochemical performance of the electrodes was tested by cyclic voltammetry (CV) in a
hydrochloric acid (HCl) aqueous solution in the presence of an Fe(III)/(II) redox couple. Results
showed that the prepared sample has a smaller ∆Ep unlike the carbon felt, which is an indicator
of a more active PAN carbonized nanofiber in comparison to the felt. Carbon nanofiber (CNF)
samples have a higher peak current, which indicates a higher surface area. | |
