| Autor: |
Reese AJ; Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States., Gelin S; Department of Materials Science and Engineering, and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Maalouf M; Department of Materials Science and Engineering, and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Wadehra N; Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States., Zhang L; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, United States., Hautier G; Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, United States., Schlom DG; Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States.; Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States., Dabo I; Department of Materials Science and Engineering, and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States., Suntivich J; Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States.; Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853, United States. |
| Abstrakt: |
The interaction between interfacial water and transition metal oxides is a primary enabling step for the oxygen evolution reaction (OER). RuO 2 is a prototypical OER electrocatalyst whose ability to activate interfacial water molecules is essential to its OER activity. We image the dissociation of surface water into OH* and O* on RuO 2 (110), where * denotes adsorbed species, using atomic force microscopy. Starting from the surface-bound water molecules, which form a one-dimensional network along the rows of Ru surface sites, increasing the oxidative potential strips hydrogen away and transforms the water molecules into OH* and O*. This oxidative step changes the pattern of the adsorbates from one- to two-dimensional. First-principles calculations with interfacial polarization, capacitive charging, and adsorbate interactions attribute this evolution to the cooperative dehydrogenation of adsorbed water and OH* on RuO 2 . We use these results to map the surface phase diagram of RuO 2 (110) and provide a quantitative interpretation of its cyclic voltammetry. Our result provides the visualization of the water dissociation on a conductive oxide surface, a critical step in the OER, and demonstrates that the water activation is a collective phenomenon at RuO 2 (110) electrodes. |
