where j is the experimentally measured current density, jd is the diffusion-limiting current density, jk is the kinetic current density, n is the number of electrons transferred, F is the Faraday constant (96485 C/mol), Do is the diffusion coefficient of O2 gas (1.9×10 -5 cm 2 /s), v is the kinematic viscosity of water (0.01 cm 2 /s), Co is the concentration of O2 gas in a solution (1.2×10 -6 mol/cm 3 )