Electrooxidation of Methanol at PANI/POAP Bilayered Structure Modified Platinum and Graphite Electrodes
By Anwar-ul-Haq Ali Shah and Nabila Yasmeen and Gul Rahman and Mazhar Mehmood and Salma Bilal
Published in Electrochimica Acta
2016
Abstract
Polyaniline/Poly(o-aminophenol) (PANI/POAP) bilayered films were deposited by electro polymerization on platinum (Pt) and graphite (Gra) electrodes for methanol oxidation in direct methanol fuel cells. The chemical composition of bilayered structure was characterized by Fourier transform infrared (FTIR) spectroscopy. Results demonstrated the presence of \FTIR\ peaks associated to \PANI\ and \POAP\ constituents confirming the bonding of \PANI\ and \POAP\ in the bilayered composite structure. The electrochemical properties of PANI/POAP electrodes were examined in pure and sulfuric acid mixed methanol solutions using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). PANI/POAP-Gra electrode showed less reactivity towards methanol oxidation, as well as poor stability upon repeated cycling. On the other hand, PANI/POAP-Pt electrode exhibited superior performance with high methanol oxidation current (Ia), capacitance (C), and specific capacitance (Cs). In addition, PANI-POAP-Pt electrode was found better than PANI-POAP-Gra electrode in terms of operation stability based on continuous cycling in methanol up to 100 cycles. The dielectric properties and \AC\ conductivity (?ac) of the PANI/POAP-Pt electrode with respect to the applied potential have been discussed.