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Title: Aqueous proton transfer across single-layer graphene

Proton transfer across single-layer graphene proceeds with large computed energy barriers and is therefore thought to be unfavourable at room temperature unless nanoscale holes or dopants are introduced, or a potential bias is applied. In this paper, we subject single-layer graphene supported on fused silica to cycles of high and low pH, and show that protons transfer reversibly from the aqueous phase through the graphene to the other side where they undergo acid–base chemistry with the silica hydroxyl groups. After ruling out diffusion through macroscopic pinholes, the protons are found to transfer through rare, naturally occurring atomic defects. Computer simulations reveal low energy barriers of 0.61–0.75 eV for aqueous proton transfer across hydroxyl-terminated atomic defects that participate in a Grotthuss-type relay, while pyrylium-like ether terminations shut down proton exchange. Finally, unfavourable energy barriers to helium and hydrogen transfer indicate the process is selective for aqueous protons.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [4] ;  [5] ;  [6] ;  [7] ;  [2] ;  [8] ;  [8] ;  [4] ;  [9] ;  [1]
  1. Northwestern Univ., Evanston, IL (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
  3. Univ. of Virginia, Charlottesville, VA (United States)
  4. Pennsylvania State Univ., University Park, PA (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Measurement Science and Systems Engineering Division
  6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Measurement Science and Systems Engineering Division
  7. Univ. of Puerto Rico, San Juan (Puerto Rico); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
  8. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
  9. Univ. of Virginia, Charlottesville, VA (United States); Univ. of Minnesota, Minneapolis, MN (United States)
Publication Date:
OSTI Identifier:
1210480
Grant/Contract Number:
ERKCC61; AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 6; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Energy Frontier Research Centers (EFRC). Fluid Interface Reactions, Structures and Transport Center (FIRST); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; catalysis (heterogeneous); solar (fuels); energy storage (including batteries and capacitors); hydrogen and fuel cells; electrodes - solar, mechanical behavior; charge transport; materials and chemistry by design; synthesis (novel materials); 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS