Active sites for the oxygen reduction reaction on the high index planes of Pt

Structural effects on the oxygen reduction reaction (ORR) have been studied on the high index planes of Pt (n(111)–(111), n(111)–(100), n(100)–(111) and n(100)–(110)) using rotating disk electrode (RDE) in 0.1M HClO4. The activity for the ORR increases with the increase of the step atom density on the surfaces with (111) terrace from n=∞ to n=5 (n is the number of terrace atomic rows), whereas the surfaces with (100) terrace do not show structural effects on the ORR activity. The activity of the surfaces with (111) terrace is higher than that on the surfaces with (100) terrace. The active sites for the ORR are located between the (111) terrace edge and the (111) terrace atomic row neighboring to the edge on Pt electrodes.