The redox peaks at 0.7, 1.1 and 1.4 V vs. reversible hydrogen electrode (RHE) could be attributed to surface transitions associated with the successive deprotonation of –H2O on the coordinatively unsaturated Ru sites (CUS) and hydrogen adsorbed to the bridging oxygen sites. At potentials relevant to the oxygen evolution reaction (OER), an –OO species on the Ru CUS sites was detected, which was stabilized by a neighboring –OH group on the Ru CUS or bridge site. Combining potential-dependent surface structures with their energetics from DFT led to a new OER pathway, where the deprotonation of the –OH group used to stabilize –OO was found to be rate-limiting.
Reshma R. Rao, Manuel J. Kolb, Niels Bendtsen Halck, Anders Filsøe Pedersen, Apurva Mehta, Hoydoo You, Kelsey A. Stoerzinger, Zhenxing Feng, Heine A. Hansen, Hua Zhou, Livia Giordano, Jan Rossmeisl, Tejs Vegge, Ib Chorkendorff, Ifan E. L. Stephens and Yang Shao-Horn
Energy Environ. Sci.,
2017, 10, 2626-2637
DOI: 10.1039/C7EE02307C
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