E_appl 0[V] Applied potential Ef 0[V] Formal potential c_bulk 1[mmol/L] Reactant concentration re 10[um] Electrode radius r_max 25*re Size of simulation space D1 1e-9[m^2/s] Reactant diffusion coefficient D2 1e-9[m^2/s] Product diffusion coefficient k0 1[m/s] Reaction rate E_start -0.4[V] Start potential E_vertex 0.4[V] Vertex potential E_step 10[mV] Potential step (output)