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Synthesis of amorphous and graphitized porous nitrogen-doped carbon spheres as oxygen reduction reaction catalysts

Authors :
R. Jürgen Behm
Maximilian Wassner
Michael S. Elsaesser
Thomas Diemant
Markus Eckardt
Andreas Reyer
Nicola Hüsing
Source :
Beilstein Journal of Nanotechnology, Beilstein Journal of Nanotechnology, Vol 11, Iss 1, Pp 1-15 (2020)
Publication Year :
2020
Publisher :
Beilstein-Institut, 2020.

Abstract

Amorphous and graphitized nitrogen-doped (N-doped) carbon spheres are investigated as structurally well-defined model systems to gain a deeper understanding of the relationship between synthesis, structure, and their activity in the oxygen reduction reaction (ORR). N-doped carbon spheres were synthesized by hydrothermal treatment of a glucose solution yielding carbon spheres with sizes of 330 ± 50 nm, followed by nitrogen doping via heat treatment in ammonia atmosphere. The influence of a) varying the nitrogen doping temperature (550–1000 °C) and b) of a catalytic graphitization prior to nitrogen doping on the carbon sphere morphology, structure, elemental composition, N bonding configuration as well as porosity is investigated in detail. For the N-doped carbon spheres, the maximum nitrogen content was found at a doping temperature of 700 °C, with a decrease of the N content for higher temperatures. The overall nitrogen content of the graphitized N-doped carbon spheres is lower than that of the amorphous carbon spheres, however, also the microporosity decreases strongly with graphitization. Comparison with the electrocatalytic behavior in the ORR shows that in addition to the N-doping, the microporosity of the materials is critical for an efficient ORR.

Details

Language :
English
ISSN :
21904286
Volume :
11
Database :
OpenAIRE
Journal :
Beilstein Journal of Nanotechnology
Accession number :
edsair.doi.dedup.....7a5758639be20e8659355167c03450df