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Title: Surface Proton Transfer Promotes Four-Electron Oxygen Reduction on Gold Nanocrystal Surfaces in Alkaline Solution

Four-electron oxygen reduction reaction (4e-ORR), as a key pathway in energy conversion, is preferred over the two-electron reduction pathway that falls short in dissociating dioxygen molecules. Gold (Au) surfaces exhibit high sensitivity of the ORR pathway to its atomic structures. The long-standing puzzle remains unsolved why the Au surfaces with {100} sub-facets were exceptionally capable to catalyze the 4e-ORR in alkaline solution, though limited within a narrow potential window. Herein we report the discovery of a dominant 4e-ORR over the whole potential range on {310} surface of Au nanocrystal shaped as truncated ditetragonal prism (TDP). In contrast, ORR pathways on single-crystalline facets of shaped nanoparticles, including {111} on nano-octahedra and {100} on nano-cubes, are similar to their single-crystal counterparts. Combining our experimental results with density functional theory calculations, we elucidate the key role of surface proton transfers from co-adsorbed H 2O molecules in activating the facet- and potential-dependent 4e ORR on Au in alkaline solutions. These results elucidate how surface atomic structures determine the reaction pathways via bond scission and formation among weakly adsorbed water and reaction intermediates. The new insight helps in developing facet-specific nanocatalysts for various reactions.
Authors:
ORCiD logo [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [1] ;  [2]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States); Columbia Univ., New York, NY (United States)
Publication Date:
Report Number(s):
BNL-114198-2017-JA
Journal ID: ISSN 0002-7863; KC0403020; TRN: US1702363
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 139; Journal Issue: 21; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; Gold nanocrystal; oxygen reduction; electrocatalysis; proton transfer; alkaline fuel cell; Center for Functional Nanomaterials
OSTI Identifier:
1389233