Pt–Ru Anode Catalyst to Suppress H 2 O 2 Formation due to Oxygen Crossover

Abstract

© 2018 The Electrochemical Society. In addition to the oxygen reduction reaction that occurs at the cathode in polymer electrolyte fuel cells, oxygen transferred through the polymer electrolyte membrane (PEM) is reduced at the anode. The quantity of H 2 O 2 generated on Pt-loaded carbon (Pt/C) and Pt-Ru alloy-loaded (Pt-Ru/C) catalysts in 0.5 M sulfuric acid solution was evaluated using a rotating ring-disk electrode method. H 2 O 2 generation on Pt/C and PtRux/C with low Ru contents (x = 0.3, 0.5) steeply increased below 0.1 V vs. SHE. In contrast, H 2 O 2 generation on PtRux/C with high Ru contents (x = 1.0, 1.5, 2.0) was suppressed, even below 0.1 V vs. SHE. PEM deterioration was evaluated by measuring the amount of fluorine emitted from lab-scale cells with anodes containing Pt/C and PtRux/C catalysts with different Ru contents. The amount of fluorine emitted from the cell with PtRux/C-containing anode decreased with increasing catalyst Ru content. PEM deterioration was suppressed by increasing Ru content in the anode catalyst due to decreased H 2 O 2 generation.