Title: Controlling the Active Sites of Sulfur-Doped Carbon Nanotube-Graphene Nanolobes for Highly Efficient Oxygen Evolution and Reduction Catalysis

Abstract

Controlling active sites of metal-free catalysts is an important strategy to enhance activity of the oxygen evolution reaction (OER). We made many attempts have been made to develop metal-free catalysts, but the lack of understanding of active-sites at the atomic-level has slowed the design of highly active and stable metal-free catalysts. We also developed a sequential two-step strategy to dope sulfur into carbon nanotube–graphene nanolobes. This bidoping strategy introduces stable sulfur–carbon active-sites. Fluorescence emission of the sulfur K-edge by X-ray absorption near edge spectroscopy (XANES) and scanning transmission electron microscopy electron energy loss spectroscopy (STEM-EELS) mapping and spectra confirm that increasing the incorporation of heterocyclic sulfur into the carbon ring of CNTs not only enhances OER activity with an overpotential of 350 mV at a current density of 10 mA cm^-2, but also retains 100% of stability after 75 h. Furthermore, the bidoped sulfur carbon nanotube–graphene nanolobes behave like the state-of-the-art catalysts for OER but outperform those systems in terms of turnover frequency (TOF) which is two orders of magnitude greater than (20% Ir/C) at 400 mV overpotential with very high mass activity 1000 mA cm^-2 at 570 mV. Moreover, the sulfur bidoping strategy shows high catalytic activity for themore » oxygen reduction reaction (ORR). Stable bifunctional (ORR and OER) catalysts are low cost, and light-weight bidoped sulfur carbon nanotubes are potential candidates for next-generation metal-free regenerative fuel cells.« less

Authors:

El-Sawy, Abdelhamid M. ^[1]; Mosa, Islam M. ^[2]; Su, Dong ^[3]; Guild, Curtis J. ^[4]; Khalid, Syed ^[5]; Joesten, Raymond ^[4]; Rusling, James F. ^[6]; Suib, Steven L. ^[7]

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+ Show Author Affiliations

1. Univ. of Connecticut, Storrs, CT (United States). Dept. of Chemistry and Inst. of Materials Science; Tanta Univ. (Egypt). Dept. of Chemistry
2. Univ. of Connecticut, Storrs, CT (United States). Dept. of Chemistry; Tanta Univ. (Egypt). Dept. of Chemistry
3. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton NY 11973 USA; Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials
4. Univ. of Connecticut, Storrs, CT (United States). Dept. of Chemistry
5. Photon Science Directorate, Brookhaven National Laboratory, Upton NY 11973 USA; Brookhaven National Lab. (BNL), Upton, NY (United States)
6. Univ. of Connecticut, Storrs, CT (United States). Dept. of Chemistry and Inst. of Materials Science
7. Univ. of Connecticut, Storrs, CT (United States). Dept. of Chemistry and Inst. of Materials Science and Chemical and Biomolecular Engineering

Publication Date:

Thu Dec 03 00:00:00 EST 2015

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)

OSTI Identifier:

1336156

Report Number(s):

BNL-112670-2016-JA
Journal ID: ISSN 1614-6832; KC0403020

Grant/Contract Number:  

SC00112704; FG02-86ER13622.A000

Resource Type:

Accepted Manuscript

Journal Name:

Advanced Energy Materials

Additional Journal Information:

Journal Volume: 6; Journal Issue: 5; Journal ID: ISSN 1614-6832

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Sulfur-Doped Carbon; oxygen reduction; Center for Functional Nanomaterials