Designing the structure of a membrane electrolyte assembly (MEA) is essential to maximizing catalyst utilization and

improving the electrode performance at the single-cell level. In this study, one-sided hot pressing was employed to enhance

catalyst utilization in an electrodeposited IrO 2 electrode for use in proton exchange membrane water electrolyzer (PEMWE)

systems. An oxygen electrode loaded with 0.13 mg Ir cm −2 IrO 2 was prepared via the anodic electrodeposition onto a Ti

porous transport layer (PTL), which was subsequently assembled with a Nafi on membrane via one-sided hot pressing. The

IrO 2 /Ti-PTL electrode penetrated the membrane, and its pores were partially fi lled with the membrane component. The mean

vertical thickness of the zone in which the IrO 2 /Ti-PTL pores are fi lled with the membrane strongly aff ected the contact area

between the electrode and electrolyte, with greater thickness resulting in a broader electrode/electrolyte interface but reduced

reactant (H 2 O) accessibility. The cell current density at 1.7 V and 80 °C was signifi cantly improved to 1.44 A cm −2 using the

one-sided hot pressing approach; these were comparable to the values reported for state-of-the-art particle-type electrodes

bearing higher loadings of platinum group metal (PGM) catalysts (~ 0.5 mg). This work highlights the great potential of

fi lm-type electrodes for use as low-PGM oxygen electrodes in PEMWEs.