As shown in Fig. 2, j(H 2 O 2) on both catalysts increased at less positive potentials, and reached the highest value at 0 V, which is consistent with the accelerated degradation of PEMs at open circuit in a single cell. 21–23 It is clear that the values of j(H 2 O 2) on the Pt xAL –PtCo/C catalyst were less than 1/2 of those on c-Pt/C at 0 ≤ E ≤ 0.06 V (practical anode potentials for ...