Polarization curves obtained with water as the only reactant flowing to the anode of a PAFC with an MEA that had been used for several TOS experiments with various diesel fuels: potential difference between the electrodes (V) versus time of water treatment (h). Anode: water flow rate = 5.1 mL/h. Cathode: air flow rate = 245 mL/min. Current density, j = 0.2 mA/cm2. Temperature = 190°C. Pressure = 1 atm.