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Title: Mechanism of oxygen reduction reaction on Pt(111) in alkaline solution: Importance of chemisorbed water on surface

Here, we report a detailed mechanistic study of the oxygen reduction reaction (ORR) on Pt(111) in alkaline solution, combining density functional theory and kinetic Monte Carlo simulations. A complex reaction network including four possible pathways via either 2e or 4e transfer is established and is able to reproduce the experimental measured polarization curve at both low- and high-potential regions. Our results show that it is essential to account for solvation by water and the dynamic coverage of *OH to describe the reaction kinetics well. In addition, a chemisorbed water (*H2O)-mediated mechanism including 4e transfers is identified, where the reduction steps via *H2O on the surface are potential-independent and only the final removal of *OH from the surface in the form of OH(aq) contributes to the current. For the ORR in alkaline solutions, such a mechanism is more competitive than the associative and dissociative mechanisms typically used to describe the ORR in acid solution. Finally, *OH and **O2 intermediates are found to be critically important for tuning the ORR activity of Pt in alkaline solution. To enhance the activity, the binding of Pt should be tuned in such a way that *OH binding is weak enough to release more surface sitesmore » under working conditions, while **O2 binding is strong enough to enable the ORR via the 4e transfer mechanism.« less
 [1] ;  [2] ;  [3]
  1. State Univ. of New York (SUNY) at Stony Brook, Stony Brook, NY (United States)
  2. State Univ. of New York (SUNY) at Stony Brook, Stony Brook, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1932-7447; R&D Project: CO009; KC0301020
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 120; Journal Issue: 28; Journal ID: ISSN 1932-7447
American Chemical Society
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States