However, the authors reported that mass transport could not be eliminated at moderate current densities for reactions with sparingly soluble reactants. Porous electrodes, which have boundarylayer thicknesses approaching the nanometer length scale, have also been suggested for determining the intrinsic kinetics of electrochemical reactions. However, the chemistry and morphology of such electrodes were found to impact observed kinetics in non-trivial ways due to the potential of overlapping boundary layers, along with the complex multiphase (gas, liquid, and sometimes solid-electrolyte phases) transport occurring in the porous medium. Therefore, continuum modeling of mass transport and the kinetics of bulk reaction occurring in an aqueous boundary layer (see below) will always be necessary for determination of Tafel parameters.