A Comparative Electrochemical Behaviour Study of p-nitrophenol Using GC and Pt Electrode

Abstract

The work reports a comparative electrochemical behavior study of p-nitrophenol using GC and Pt electrode.  For this purpose, Cyclic Voltammetry was employed, where the redox mechanisms could be compared for reduction processes of p-nitrophenol by analysis of the voltammetric responses. Voltammetric curves of p-nitrophenol in aqueous-methanol medium on different pH using B.R. buffer for various concentrations (0.05mM, 0.1 mM, 0.15mM, 0.2mM) and scan rates at GC and Pt electrode was obtained. The very complicated reduction of p-nitrophenol revealed three reduction peaks out of which two peaks are irreversible and one peak is reversible.

Equation 1

HOC₆H₄NO₂     +    e^-                                            HOC₆H₄NO₂∙^-

Equation 2

HOC₆H₄NO₂∙^- +  HOC₆H₄NO₂        HOC₆H₄NO₂H^.   +  ^-OC₆H₄NO₂

Equation 3

HOC₆H₄NO₂H^.             +  HOC₆H₄NO₂∙^-              HOC₆H₄NO₂H^-  +   HOC₆H₄NO₂

Equation4

HOC₆H₄NO₂H^-             +  HOC₆H₄NO₂                HOC₆H₄NO       +  ^-OC₆H₄NO₂ +H₂O         

The result obtained from GC electrode proved to be better than Pt electrode. Hence the GC electrode can be considered a suitable tool for determination of redox mechanism of  p-nitrophenol.