Fig. 4: Performance stability and CO resistance.

a, b HOR polarization curves for MoNi4 and WNi4 alloys in H2-saturated 0.1 M KOH before and after 2000 cycles, respectively. c Chronoamperometry (j – t) responses recorded on MoNi4, WNi4, and Pt/C catalysts at a 60 mV overpotential in H2-saturated 0.1 M KOH. d HOR polarization curves for MoNi4 and Pt/C alloys in H2-saturated 0.1 M KOH with (dashed lines) and without (solid lines) the presence of 20,000 p.p.m. CO.