R_O_2_,T_ = 4_F_C_O_2_,c_h_i_l_i_m_ = R_O_2_,G_D_L_ + R_O_2_,M_P_L_M_ + R_O_2_,M_P_L_K_n_ + R_O_2_,C_L_ (5) where C_O_2_,c_h_ is gas concentration at the channel, i_l_i_m_ is limiting current density, F is Faraday constant.