4.4 Preparation of Pt/C electrode
Pt/C (nominally 20% on carbon black, Thermo Fisher Scientific) 30 mg and 5 mg polyvinylidene fluoride (PVDF) were mixed in 500 μL N-methyl-2-pyrrolidone (NMP). The 50 μL ink solution was deposited evenly onto a 1×1 cm2 carbon paper. The electrode was dried in an oven at 80 °C for 24 h. The loading amount onto the carbon paper was about ~5 mg.