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Title: Critical role of intercalated water for electrocatalytically active nitrogen-doped graphitic systems

Graphitic materials are very essential in energy conversion and storage because of their excellent chemical and electrical properties. The strategy for obtaining functional graphitic materials involves graphite oxidation and subsequent dissolution in aqueous media, forming graphene-oxide nanosheets (GNs). Restacked GNs contain substantial intercalated water that can react with heteroatom dopants or the graphene lattice during reduction. We demonstrate that removal of intercalated water using simple solvent treatments causes significant structural reorganization, substantially affecting the oxygen reduction reaction (ORR) activity and stability of nitrogen-doped graphitic systems. Amid contrasting reports describing the ORR activity of GN-based catalysts in alkaline electrolytes, we demonstrate superior activity in an acidic electrolyte with an onset potential of ~0.9 V, a half-wave potential (E½) of 0.71 V, and a selectivity for four-electron reduction of >95%. Finally and further, durability testing showed E½ retention >95% in N2- and O2-saturated solutions after 2000 cycles, demonstrating the highest ORR activity and stability reported to date for GN-based electrocatalysts in acidic media.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1] ;  [5] ;  [4] ;  [6] ;  [6] ;  [7] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Physics and Applications Division
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Physics and Applications Division; Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Biological Engineering
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division
  4. Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Chemical and Biological Engineering
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Chemistry Division
  6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division. Center for Nanophase Materials Sciences
  7. Rutgers Univ., Piscataway, NJ (United States). Science and Engineering
Publication Date:
OSTI Identifier:
1261296
Grant/Contract Number:
AC05-00OR22725; AC52-06NA25396; AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Science Advances
Additional Journal Information:
Journal Volume: 2; Journal Issue: 3; Journal ID: ISSN 2375-2548
Publisher:
AAAS
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC); Los Alamos National Lab. (LANL), Los Alamos, NM (United States);
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE electrocatalysts; intercalated water; graphene oxide; oxygen reduction