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Influence of the Structure-Forming Agent on the Performance of Fe-N-C Catalysts

Schardt, Sven and Weidler, Natascha and Wallace, W. and Martinaiou, Ioanna and Stark, Robert and Kramm, Ulrike :
Influence of the Structure-Forming Agent on the Performance of Fe-N-C Catalysts.
[Online-Edition: https://doi.org/10.3390/catal8070260]
In: Catalysts, 8 (7) p. 260. ISSN 2073-4344
[Article] , (2018)

Official URL: https://doi.org/10.3390/catal8070260

Abstract

In this work, the influence of the structure-forming agent on the composition, morphology and oxygen reduction reaction (ORR) activity of Fe-N-C catalysts was investigated. As structure-forming agents (SFAs), dicyandiamide (DCDA) (nitrogen source) or oxalic acid (oxygen source) or mixtures thereof were used. For characterization, cyclic voltammetry and rotating disc electrode (RDE) experiments were performed in 0.1 M H2SO4. In addition to this, N2 sorption measurements and Raman spectroscopy were performed for the structural, and elemental analysis for chemical characterization. The role of metal, nitrogen and carbon sources within the synthesis of Fe-N-C catalysts has been pointed out before. Here, we show that the optimum in terms of ORR activity is achieved if both N- and O-containing SFAs are used in almost similar fractions. All catalysts display a redox couple, where its position depends on the fractions of SFAs. The SFA has also a strong impact on the morphology: Catalysts that were prepared with a larger fraction of N-containing SFA revealed a higher order in graphitization, indicated by bands in the 2nd order range of the Raman spectra. Nevertheless, the optimum in terms of ORR activity is obtained for the catalyst with highest D/G band ratio. Therefore, the results indicate that the presence of an additional oxygen-containing SFA is beneficial within the preparation.

Item Type: Article
Erschienen: 2018
Creators: Schardt, Sven and Weidler, Natascha and Wallace, W. and Martinaiou, Ioanna and Stark, Robert and Kramm, Ulrike
Title: Influence of the Structure-Forming Agent on the Performance of Fe-N-C Catalysts
Language: English
Abstract:

In this work, the influence of the structure-forming agent on the composition, morphology and oxygen reduction reaction (ORR) activity of Fe-N-C catalysts was investigated. As structure-forming agents (SFAs), dicyandiamide (DCDA) (nitrogen source) or oxalic acid (oxygen source) or mixtures thereof were used. For characterization, cyclic voltammetry and rotating disc electrode (RDE) experiments were performed in 0.1 M H2SO4. In addition to this, N2 sorption measurements and Raman spectroscopy were performed for the structural, and elemental analysis for chemical characterization. The role of metal, nitrogen and carbon sources within the synthesis of Fe-N-C catalysts has been pointed out before. Here, we show that the optimum in terms of ORR activity is achieved if both N- and O-containing SFAs are used in almost similar fractions. All catalysts display a redox couple, where its position depends on the fractions of SFAs. The SFA has also a strong impact on the morphology: Catalysts that were prepared with a larger fraction of N-containing SFA revealed a higher order in graphitization, indicated by bands in the 2nd order range of the Raman spectra. Nevertheless, the optimum in terms of ORR activity is obtained for the catalyst with highest D/G band ratio. Therefore, the results indicate that the presence of an additional oxygen-containing SFA is beneficial within the preparation.

Journal or Publication Title: Catalysts
Volume: 8
Number: 7
Publisher: MDPI
Uncontrolled Keywords: Fe-N-C catalyst, oxygen reduction reaction
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Catalysts and Electrocatalysts
11 Department of Materials and Earth Sciences > Material Science > Physics of Surfaces
Exzellenzinitiative
Exzellenzinitiative > Clusters of Excellence
Exzellenzinitiative > Clusters of Excellence > Center of Smart Interfaces (CSI)
Date Deposited: 16 Jul 2018 05:32
DOI: 10.3390/catal8070260
Official URL: https://doi.org/10.3390/catal8070260
Funders: This research was funded by the German ministry of education and research (BMBF) by grant number 03XP0092., In addition, I.M. and U.I.K. like to acknowledge further funding by the Graduate School of Excellence Energy Science and Engineering (GSC1070) funded by the German research foundation (DFG).
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