Structural effects on the oxygen reduction reaction on the high index planes of Pt3Co

Abstract

The oxygen reduction reaction (ORR) has been studied on the n(111)–(111) and n(111)–(100) series of Pt₃Co using a hanging meniscus rotating disk electrode (HMRDE) in 0.1 M HClO₄ (n is the number of terrace atomic rows). The activity for the ORR on the n(111)–(111) series, which is estimated by the specific activity at 0.90 V (RHE) j_k, increases linearly with an increase in the step atom density d_S. On the other hand, the activity for the ORR on the n(111)–(100) series increases linearly with an increase of d_S on the surfaces with n ≥ 9. On the surfaces with n < 9, however, the activity for the ORR decreases with an increase of d_S. We find a correlation between the ORR activity and θ_OH at the step on the assumption that all the oxide species are Pt–OH.