Kinetics determination of electrogenerated hydrogen peroxide (H₂O₂) using carbon fiber microelectrode in electroenzymatic degradation of phenolic compounds

The kinetics of electrogenerated hydrogen peroxide (H₂O₂), which can activate peroxidases in an electroenzymatic process, was examined by an amperometric technique using a carbon fiber microelectrode that was modified by polyaniline (PAn) film and platinum particles. The electrogeneration of H₂O₂ was found to be dependent on the pH and applied potential, and resulting in a variable current response of the carbon fiber microelectrode. The highest amount of H₂O₂ was electrogenerated when 2.3 V was applied between the Pt/Ti anode and a reticulated vitreous carbon (RVC) cathode at pH 6.0, with a current response of 0.0190 μA min^-1. Phenol was completely degraded by the electroenzymatic reaction of the immobilized horseradish peroxidase (HRP), and the time required for the electrogeneration of H₂O₂ increased according to the initial concentration of phenol. The degradation stoichiometric ratio between the electrogenerated H₂O₂ and the aqueous phenol under HRP immobilized on RVC was found to be 1:1.