| Abstract
| - Oxygen reduction reaction (ORR) activity and H2O2 formation at Pt54Fe46, Pt68Co32, and Pt63Ni37 electrodesin 0.1 M HClO4 solution at 20 to 90 °C were investigated by using a channel flow double electrode method.In the temperature range of 20−50 °C, the apparent rate constants kapp for ORR at these electrodes werefound to be 2.4−4.0 times larger than that at a pure Pt electrode, whereas their apparent activation energiesof 41 kJ mol-1 at −0.525 V vs E° (0.760 V vs RHE at 30 °C) were comparable to that at the Pt electrode.H2O2 yield was ca. 1.0% at Pt54Fe46 and ca. 0.16% at Pt68Co32 and Pt63Ni37 between 0.3 and 1.0 V vs RHE.The kapp values at the alloy electrodes decreased with elevating temperature above 60 °C, and settled toalmost the same values at the Pt electrode. The H2O2 production was not detected at the alloy electrodes onceheated at the high temperature in the solution, probably due to the thickening of the Pt skin-layer by aconsiderable dissolution of nonprecious metal components (Fe, Co, Ni) from the alloys.
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