Electrochemical oxidation of 2,4,6-trichlorophenol on iron-doped nanozirconia ceramic

Solvothermaly synthesized zirconium oxide nanopowders, pure and doped with various amounts of iron ions (1-20 %), were used as modifiers of glassy carbon electrodes. The modified electrodes were tested in the reaction of electrochemical oxidation of 2,4,6-trichlorophenol (TCP) in order to investigate the influence of doping on electrochemical performance of zirconia matrix. The techniques of cyclic voltammetry and electrochemical impedance spectroscopy were employed. Cyclic voltammetry showed that electrooxidation of TCP proceeded through the oxidation of hydroxyl group. Possible pathway included the formation of quinones and the formation of polyphenol film on the electrode surface, leading to the electrode fouling. Iron doping enhanced the activity of zirconia matrix towards TCP electrooxidation. Electrochemical impedance spectroscopy showed the importance of iron content in zirconia matrix for the preferable pathway of TCP electrooxidation. The quinone formation pathway was favoured by low iron doped zirconia (doped with 1% of iron), while polyphenol film formation on the electrode surface was more pronounced at samples with higher iron ion content (for doping with 10 and 20 % of iron). The sample with 5 % of added iron ions, showed intermediate behaviour, where the formed polyphenol film showed slight degradation.

Automated summary

Solvothermally synthesized zirconium oxide nanopowders, pure and doped with different amounts of iron ions, were used to modify glassy carbon electrodes for the electrochemical oxidation of 2,4,6-trichlorophenol. The results showed that iron doping enhanced the activity of zirconia matrix towards TCP electrooxidation, with different iron contents affecting the oxidation pathway of TCP. The formation of polyphenol film on the electrode surface was more pronounced with higher iron ion content.