influenced by the porosity of the electrodes. This result implies
that the hot-pressing of an MEA at 3.0 MPa renders the
most favorable MEA structure with an optimal three-phase
boundary and a suitable pore structure of the catalyst layers.
Application of a high pressure beyond the optimal value may
deteriorate the pore structure of the cathode causing detrimental
effects to the electrochemically active surface area
(ECSA) and to the mass transport characteristics of the reactants
and products [7,25].