In the presence of phenol (Figure ), the bioelectronic CV with an additional pre-peak on the cathodic scan was observed, which is driven by the exergonic reduction of the resulting HO2 • /hdroperoxyl anion (HO2 -) after the primary electrode process associated with PT, leading to the irreversible overall reduction of O2 to H2O2. Conversely, in the presence of pyrazine