Abstract:
Polyaniline (PANI) and PANI/TiO2 composite was potentio dynamically deposited from
solutions of 0.1M aniline /1M HCl and in the presence of 0.04 g TiO2 on bare and graphite
(Gr) modified glassy carbon (GC) electrode. These materials and PANI/TiO2/Gr was also
prepared chemically using in situ oxidation polymerization method to compare their
electrochemical and capacitive property. The nano composite characterized using scanning
electron microscope (SEM), X-ray electron diffraction (XRD), Ultra violet visible (Uv-vis) and
Fourier transforms infrared (FTIR) spectroscopy. The morphology of PANI/TiO2/Gr exhibited
uniform and revels good pores. The crystal size of the nano composites are estimated from
XRD. Besides Uv-vis and FTIR result indicates the presences of PANI and the success full
preparation of the nano composites. The electro chemical characterization of PANI,
PANI/TiO2 and PANI/TiO2/Gr was carried out by employing cyclic voltametry (CV) and
electrochemical impedance spectroscopy (EIS).CV analysis showed a higher specific
capacitance of PANI/TiO2/Gr (4864 F/g) for 10 potential cycles) electro chemically formed on
Gr/GC electrodes at scan rate of 10 mV/s than PANI (642 F/g) and PANI/TiO2 (2539 F/g).While the specific capacitance of chemically formed once was slightly lower PANI/TiO2/Gr
(1944 F/g), PANI (713 F/g), PANI/TiO2 (1587 F/g). The dependence of capacitance with scan
rate investigation illustrates, drops slowly from its initial value as the scan rate increases. The
stability of the nano composites studied using CV at scan rate of 50 mV/s indicates the better
performance of PANI/TiO2/Gr nano composites which retains 81% of its capacitance at 50th
cycle. In addition to this, a large specific energy 0.0659 J and specific energy density 2259
Wh/Kg was found for PANI/TiO2/Gr. Furthermore, EIS study indicates the charge transfer
resistance (Rct) and solution resistance (Rs) of the PANI/TiO2/Gr nanocomposites revels very
low than PANI and PANI/TiO2. The study demonstrates the materials for electro chemical
capacitors with advantages including low charge transfer resistance, high specific energy
density and stability due to synergistic effects of each component on electro chemical,
structure, morphology and conductivity.
