Özet:

In this study, modified electrode systems were prepared to be used directly in methanol fuel cells. To examine the electrochemical behavior of the modified electrode systems for methanol oxidation, cyclic voltammetry (CV), chronoamperometry (CHR), and electrochemical impedance spectroscopy (EIS) methods were used. Pencil tip graphite (KUG) used as the working electrode. Optimizations of voltage range, scanning speed, number of cycles and acid concentration in anhydrous medium, were made for electropolymerization of thiophene (Th) on the surface of the KUG electrode by CV method. Then, platinum (Pt) as a catalyst, was doped on the polymer film at 4 different concentrations (3, 3.25, 3.50 and 3.75mM). The electrochemical behavior of the modified electrode systems for methanol oxidation was investigated and interpreted. In addition, SEM-EDS analyzes of the modified electrode systems which used in the study were performed to be informed about the morphological structures of the polymer films and the amount of Pt doped to the films. Based on the results; when the conductive polymer film and Pt are used as catalyst separately for methanol oxidation, the responses are almost similar. However, when conductive polymer used as a support material for Pt as catalyst, it exposes very high methanol oxidation performance. The electrochemical active surface area (ECSA) and specific capacitance (Cs) values for the modified electrodes were calculated using the data obtained from the results of CV and EIS methods. The highest calculated ECSA and Cs values are 1.17 m2/gr and 0.21 Fg-1, respectively, and belonging to the KUG/3.50mMPt@PTh electrode.

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