engleski

The effect of polyaniline morphology on hydroquinone/quinone redox reaction

The catalytic effect of polyaniline (PANI) on H_2Q/Q redox reaction has been investigated in relationship to the different morphology which is known to depend on counter-ions during the synthesis. It is established that PANI lowers H_2Q/Q reaction potential, as well as the potential difference, delta E_p, obtained by cyclic voltammetry. It is shown that the decrease in delta E_p does not depend on the increase of PANI layer thickness, and there is no difference in the case of PANISO_4 and PANICl electrode. The increase of I_p values in cyclic voltammograms of PANI, as well as in I_lim in rde measurements, compared to Pt-electrodes, is explained by the increase of the real surface area of PANI electrodes, and the difference in PANISO_4 and PANICl by the different morphology. In general, the redox reaction on PANI electrodes is explained by the specific adsorption of H_2Q molecules onto EM^2+ centres. The inclined current plateau obtained by rde measurements is explained by the slow process in recombination of the reduced PANI (LE) to the oxidised form (EM^2+) which at high concentrations of H_2Q becomes the rate determining step in the overall reaction.

counter-ion influence; electrocatalysis; morphology; polyaniline; quinone/hydroquinone

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