Next, similar CVs of O2/O2 •-in the potential range from -0.5 to -2.0 V vs. Fc + , Fc were measured (Figure , experimented: line and simulated: open circle). Along the sequential cyclic scans at 0.1 V s -1 , peaks of Q •-produced through the 2PCET appear, pc2/pa2 (Q •-/Q 2-, Equation ( ), E°Q2) and pa3 (Q/Q •-, Equation (11), E°Q1). In the cathodic scan, a peak of Q/Q •-don't appear at the potential corresponding to its redox couple around -0.790 V, because Q is not generated before the 2PCET (Supporting Information, Figure ), which is triggered by the electrogeneration of O2 •-. The peaks derived of Q •-immediately appear at 0.1 V s -1 or more fast scan rates, suggesting that the kinetics of 2PCET was superior up to step (ii), although that of step (iii) is unclear.