Ptru c

To prepare anode catalyst ink, 4 mg of Pt-Ru/C (40 wt % Pt and 20 wt % Ru, Johnson Matthey) was added into the mixture of 100 μl of PTFE (polytetrafluoroethylene) solution (15 wt %) and 100 μl of isopropanol. After dispersing ultrasonically for 10 min, the slurry was coated on a nickel foam (1.14 cm²) and then stored in 6 M KOH solution. The total metal (Pt + Ru) loading was 3.5 mg cm⁻². Similarly, 2 mg of commercial Pt/C (60 wt %) or Pd-Te HPs/C and 12 μl of Nafion solution (5 wt %) were dispersed in 600 μl of isopropanol and then coated on a gas diffusion layer to obtain cathode. To exchange H⁺ in Nafion, the as-prepared cathode was immersed in 6 M KOH solution overnight. The cathode loading was 1.75 mg cm⁻² for both catalysts. To obtain KOH-doped polybenzimidazole (PBI) membrane, the PBI membrane (20 μm) was treated by 6 M KOH solution at 80°C for 5 hours and then stored in 6 M KOH solution. Finally, the MEA was fabricated by hot pressing a Pt-Ru/C anode, a Pt/C or Pd-Te HPs/C cathode, and a KOH-doped PBI membrane at 130°C and 1 MPa for 30 s. The active area of membrane electrode assembly (MEA) was 1.14 cm².