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Mazzucato M, Gavioli L, Balzano V, Berretti E, Rizzi GA, Badocco D, Pastore P, Zitolo A, Durante C. Synergistic Effect of Sn and Fe in Fe-N x Site Formation and Activity in Fe-N-C Catalyst for ORR. ACS APPLIED MATERIALS & INTERFACES 2022; 14:54635-54648. [PMID: 36468946 PMCID: PMC9756292 DOI: 10.1021/acsami.2c13837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
Iron-nitrogen-carbon (Fe-N-C) materials emerged as one of the best non-platinum group material (non-PGM) alternatives to Pt/C catalysts for the electrochemical reduction of O2 in fuel cells. Co-doping with a secondary metal center is a possible choice to further enhance the activity toward oxygen reduction reaction (ORR). Here, classical Fe-N-C materials were co-doped with Sn as a secondary metal center. Sn-N-C according to the literature shows excellent activity, in particular in the fuel cell setup; here, the same catalyst shows a non-negligible activity in 0.5 M H2SO4 electrolyte but not as high as expected, meaning the different and uncertain nature of active sites. On the other hand, in mixed Fe, Sn-N-C catalysts, the presence of Sn improves the catalytic activity that is linked to a higher Fe-N4 site density, whereas the possible synergistic interaction of Fe-N4 and Sn-Nx found no confirmation. The presence of Fe-N4 and Sn-Nx was thoroughly determined by extended X-ray absorption fine structure and NO stripping technique; furthermore, besides the typical voltammetric technique, the catalytic activity of Fe-N-C catalyst was determined and also compared with that of the gas diffusion electrode (GDE), which allows a fast and reliable screening for possible implementation in a full cell. This paper therefore explores the effect of Sn on the formation, activity, and selectivity of Fe-N-C catalysts in both acid and alkaline media by tuning the Sn/Fe ratio in the synthetic procedure, with the ratio 1/2 showing the best activity, even higher than that of the iron-only containing sample (jk = 2.11 vs 1.83 A g-1). Pt-free materials are also tested for ORR in GDE setup in both performance and durability tests.
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Affiliation(s)
- Marco Mazzucato
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, 35131Padova, Italy
| | - Luca Gavioli
- i-LAMP
& Department of Mathematics and Physics, Università Cattolica del Sacro Cuore, Via della Garzetta 46, 25133Brescia, Italy
| | - Vincenzo Balzano
- i-LAMP
& Department of Mathematics and Physics, Università Cattolica del Sacro Cuore, Via della Garzetta 46, 25133Brescia, Italy
| | - Enrico Berretti
- Institute
of Chemistry of Organometallic Compounds (ICCOM)—National Research
Council (CNR), Via Madonna
del Piano 10, 50019Sesto Fiorentino, Italy
| | - Gian Andrea Rizzi
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, 35131Padova, Italy
| | - Denis Badocco
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, 35131Padova, Italy
| | - Paolo Pastore
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, 35131Padova, Italy
| | - Andrea Zitolo
- Synchrotron
SOLEIL, L’Orme des Merisiers, BP 48 Saint Aubin, 91192Gif-sur-Yvette, France
| | - Christian Durante
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, 35131Padova, Italy
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Najóczki F, Szabó M, Lihi N, Udvardy A, Fábián I. Synthesis and Characterization of 1,10-Phenanthroline-mono- N-oxides. Molecules 2021; 26:molecules26123632. [PMID: 34198594 PMCID: PMC8231831 DOI: 10.3390/molecules26123632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 11/16/2022] Open
Abstract
N-oxides of N-heteroaromatic compounds find widespread applications in various fields of chemistry. Although the strictly planar aromatic structure of 1,10-phenanthroline (phen) is expected to induce unique features of the corresponding N-oxides, so far the potential of these compounds has not been explored. In fact, appropriate procedure has not been reported for synthesizing these derivatives of phen. Now, we provide a straightforward method for the synthesis of a series of mono-N-oxides of 1,10-phenanthrolines. The parent compounds were oxidized by a green oxidant, peroxomonosulfate ion in acidic aqueous solution. The products were obtained in high quality and at good to excellent yields. A systematic study reveals a clear-cut correlation between the basicity of the compounds and the electronic effects of the substituents on the aromatic ring. The UV spectra of these compounds were predicted by DFT calculations at the TD-DFT/TPSSh/def2-TZVP level of theory.
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Affiliation(s)
- Ferenc Najóczki
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (F.N.); (M.S.); (N.L.)
- Doctoral School of Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
| | - Mária Szabó
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (F.N.); (M.S.); (N.L.)
| | - Norbert Lihi
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (F.N.); (M.S.); (N.L.)
- MTA-DE Homogeneous Catalysis and Reaction Mechanisms Research Group, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
| | - Antal Udvardy
- Department of Physical Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary;
| | - István Fábián
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary; (F.N.); (M.S.); (N.L.)
- MTA-DE Homogeneous Catalysis and Reaction Mechanisms Research Group, University of Debrecen, Egyetem tér 1, H-4032 Debrecen, Hungary
- Correspondence: ; Tel.: +36-52-512-900 (ext. 22378); Fax: +36-52-518-660
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Mikulski CM, Gelfand LS, Schwartz ES, Pytlewski LL, Karayannis NM. Main group metal(II) tetrafluoroborate interactions with 2,6-lutidine N-oxide. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0022-1902(81)80533-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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