Electron Transfer Processes at Aryl‐Modified Glassy Carbon Electrode

Abstract

Abstract The effect of a layer of electrochemically grafted 4‐diazo‐ N , N ‐diethylaniline (DEA) groups on the electron transfer kinetics of redox systems, displaying fast and slow heterogeneous electron transfer rate constants at edge and basal planes of carbon, was investigated. The properties of the modified electrode were characterized by cyclic voltammetry using four different inorganic redox systems (Fe(CN) $\rm{ {_{6}^{3-/4-}}}$ , Co(phen) $\rm{ {_{3}^{2+/3+}}}$ , Ru(NH 3 ) $\rm{ {_{6}^{2+/3+}}}$ , and IrCl $\rm{ {_{6}^{2-/3-}})}$ in acidic, neutral, and basic media. Two distinct blocking behaviors and electrostatic effects were observed. More precisely, a strong blocking effect of the grafted layer on Fe(CN) $\rm{ {_{6}^{3-/4-}}}$ and Co(phen) $\rm{ {_{3}^{2+/3+}}}$ was found, whereas Ru(NH 3 ) $\rm{ {_{6}^{2+/3+}}}$ and IrCl $\rm{ {_{6}^{2-/3-}}}$ showed to be rather unaffected by the presence of the DEA grafted layer.