Electrochemical study of glassy carbon electrodes modified with zirconium phosphate and some azine-type redox dyes

Glassy carbon (GC) electrodes were modified with a layer of zirconium phosphate (ZrP), using either direct chemical synthesis onto the surface or a ZrP gel droplet evaporation procedure. The azine-type dyes nile blue A (NB) and toluidine blue O (TB) were immobilized onto the ZrP-modified GC electrodes either by adsorption onto just the formed layer of ZrP or by inclusion into the ZrP matrix during its chemical synthesis. The electrochemical behavior of the GC·ZrP·dye composite electrodes was studied. For GC·ZrP-modified electrodes prepared by chemical synthesis on the surface, coverage by NB or TB of one or a few monolayers was found, with E _m values for these redox couples slightly shifting by ca. 0.05 V to the negative direction. For the GC·ZrP electrodes prepared by gel droplet evaporation, the E _m values for NB and TB appear initially shifted by ca. 0.2 V to the positive direction; however, both cathodic and anodic peaks return to their usual positions on the potential scale during soaking these electrodes in a buffer solution. Electronic Publication