Structural effects on the activity for the oxygen reduction reaction on n(111)-(100) series of Pt: correlation with the oxide film formation

The oxygen reduction reaction (ORR) have been studied on n(1 1 1)-(1 0 0) series of Pt using hanging meniscus rotating disk electrode (HMRDE) in 0.1 M HClO4 (n is the number of terrace atomic rows). The activity for the ORR, which is estimated by the reduction current density at 0.90 V (RHE)j(ORR,0.90V), increases linearly with the increase of the step atom density d(S) on the surfaces with 5 <= n. On the surfaces with n < 5, however, the activity for the ORR decreases with the increase of d(S). The deactivation of the ORR on the surfaces with n < 5 correlates with the formation of PtO-like species at the step. (C) 2012 Elsevier Ltd. All rights reserved.