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

Ulises Martinez; Joseph H Dumont; Edward F Holby; Kateryna Artyushkova; Geraldine M Purdy; Akhilesh Singh; Nathan H Mack; Plamen Atanassov; David A Cullen; Karren L More; Manish Chhowalla; Piotr Zelenay; Andrew M Dattelbaum; Aditya D Mohite; Gautam Gupta

doi:10.1126/sciadv.1501178

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

Sci Adv. 2016 Mar 18;2(3):e1501178. doi: 10.1126/sciadv.1501178. eCollection 2016 Mar.

Authors

Affiliations

¹ Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
² Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.; Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, NM 87131, USA.
³ Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
⁴ Department of Chemical and Biological Engineering, University of New Mexico, Albuquerque, NM 87131, USA.
⁵ Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
⁶ Materials Science and Technology Division, Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
⁷ Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, NJ 08854, USA.

Abstract

Graphitic materials are 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 (E ½) of 0.71 V, and a selectivity for four-electron reduction of >95%. Further, durability testing showed E ½ 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.

Keywords: Electrocatalysts; graphene oxide; intercalated water; oxygen reduction.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Catalysis
Electrochemistry
Graphite / chemistry*
Models, Theoretical
Nitrogen / chemistry*
Oxidation-Reduction
Oxides / chemistry
Oxygen / chemistry
Solvents
Spectroscopy, Fourier Transform Infrared
Water / chemistry*
X-Ray Diffraction

Substances

Oxides
Solvents
Water
Graphite
Nitrogen
Oxygen