To provide further evidence on this important phenomenon, we have extended our study by performing carefully designed accelerated degradation tests (ADTs) in 50 cm 2 single-cells at various LVLs and temperatures using the d-Pt-Ni/C-JM benchmark as the cathode electrocatalyst. Figure shows the decrease in mV at 1.2 A cm -2 , in 50 cm 2 single-cells, observed upon exposing the cathode catalyst layer to these ADTs (1000 cycles, 0.925-0.X VRHE; X=70/60/50, 3 second hold at both LVL and UVL; ambient outlet pressures, stoichiometry 1.5/2, dew point 50 o C anode and cathode; H2/N2). The results clearly indicate that the highest voltage losses have been observed in the case of ADT conditions with LVL of 0.50 VRHE, whereas the voltage losses decrease dramatically if the LVL is increased to 0.60 or 0.70 VRHE respectively. The trends presented in Figure reveal another important parameter highly relevant for Pt-alloy cathodes. Regardless of the LVL used in the ADT (0.7, 0.6 or 0.5 V), the observed cell voltage losses after the ADT significantly increase with temperatures above 60 o C. This is, however, to be expected since temperature is also known to affect the kinetics of Pt-oxide formation and reduction, influencing the onsets . Consequently, at the same LVL, a higher fraction of Pt-oxide gets reduced with increasing temperature, leading to a lower protection of the less noble metal towards the dissolution and thus, a higher voltage loss. Both the effects of the voltage window as well as the temperature are in line with our recent liquid electrolyte follow-up study .