These employed 250 µm thick H23C9 carbon paper and MPLs (Freudenberg, Germany) with hydrophobic treatment to facilitate water removal. The GDEs were cut into two 5 × 5 cm squares and sandwiched between an 8 × 8 cm square of Nafion™ 211 membrane (DuPont, USA), with a thickness of 25.4 µm. Using a hot press (Carver Inc., USA), the GDEs and membrane were pressed together for 3 minutes at 140 °C, with a clamping pressure of 2.75 MPa to bond the layers together and form the MEA .