The effect of polyaniline morphology on hydroquinone/quinone redox reaction
2001; Elsevier BV; Volume: 46; Issue: 18 Linguagem: Inglês
10.1016/s0013-4686(01)00491-1
ISSN1873-3859
Autores Tópico(s)Electrochemical sensors and biosensors
ResumoThe catalytic effect of polyaniline (PANI) on the hydroquinone/quinone (H2Q/Q) redox reaction, has been investigated with respect to different morphologies which are known to depend on the counter-ions during the synthesis. It has been established that PANI lowers the H2Q/Q reaction potential, as well as the potential difference, ΔEp, obtained by cyclic voltammetry. It is shown that the decrease in ΔEp does not depend on the increase in the thickness of the PANI layer, and there is no difference in the case of PANISO4 and PANICl electrode. The increase in the Ip values in the cyclic voltammograms of PANI, as well as in Ilim in rotating disc electrodes (RDE) measurements, compared to Pt-electrodes, is explained by the increase in the real surface area of PANI electrodes, and the difference in PANISO4 and PANICl by the different morphologies. In general, the redox reaction on PANI electrodes is explained by the specific adsorption of H2Q molecules onto EM2+ centres. The inclined current plateau obtained by RDE measurements is explained by the slow process in the recombination of the reduced PANI (LE) to the oxidised form (EM2+) which in the presence of high concentrations of H2Q becomes the rate-determining step in the overall reaction.
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