A comparative investigation of the electrocatalytic oxidation of methanol on poly-NiTCPP and poly-TCPP/Ni modified glassy carbon electrodes

摘要

Electro-oxidation of methanol in alkaline solution at a glassy carbon electrode electrochemically modified by a conductive polymeric meso-tetra(4-carboxyphenyl)porphyrinato nickel(II), abbreviated as poly-NiTCPP and also meso-tetra(4-carboxyphenyl)porphyrin with incorporated nickel(II) cations, abbreviated as, poly-TCPP/Ni, were investigated and compared. Both films were prepared by oxidative electro-polymerization of complexes by repetitive cyclic voltammetry (RCV) in 0.1 M NaOH aqueous solution. The electrochemical properties and behaviors and also kinetic values of both films have been characterized and compared using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Similar rate constants (1.48 x 10(5) and 1.40 x 10(5) cm(3) mol(-1) s(-1)) and also, the electron transfer coefficients (alpha = 0.54 and 0.58) were determined for methanol electro-oxidation on the surface of GC/poly-NiTCPP and GC/poly-TCPP/Ni electrodes, respectively. Impedance spectroscopy was used to investigate the catalytic oxidation of methanol on the surface of the modified electrodes. Finally, it has been shown that the both electrodes have an acceptable long-term (checked up to 1 month) stability toward methanol oxidation.