Chemical Kinetic Method for Active-Site Quantification in Fe-N-C Catalysts and Correlation with Molecular Probe and Spectroscopic Site-Counting Methods.

Autor: Bates JS; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Martinez JJ; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Hall MN; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Al-Omari AA; Department of Chemical and Biomolecular Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Murphy E; Department of Chemical and Biomolecular Engineering, National Fuel Cell Research Center, University of California, Irvine, California 92697, United States., Zeng Y; Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States., Luo F; The Electrochemical Catalysis, Energy and Materials Science Laboratory, Department of Chemistry, Technical University Berlin, 10623 Berlin, Germany., Primbs M; The Electrochemical Catalysis, Energy and Materials Science Laboratory, Department of Chemistry, Technical University Berlin, 10623 Berlin, Germany., Menga D; Chair of Technical Electrochemistry, Department of Chemistry and Catalysis Research Center, Technische Universität München (TUM), 85748 Garching, Germany., Bibent N; ICGM, Univ. Montpellier, CNRS, ENSCM, 34293 Montpellier, France., Sougrati MT; ICGM, Univ. Montpellier, CNRS, ENSCM, 34293 Montpellier, France., Wagner FE; Department of Physics, Technische Universität München (TUM), 85748 Garching, Germany., Atanassov P; Department of Chemical and Biomolecular Engineering, National Fuel Cell Research Center, University of California, Irvine, California 92697, United States., Wu G; Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States., Strasser P; The Electrochemical Catalysis, Energy and Materials Science Laboratory, Department of Chemistry, Technical University Berlin, 10623 Berlin, Germany., Fellinger TP; Division 3.6 Electrochemical Energy Materials, Bundesanstalt für Materialforschung und -prüfung (BAM), 12203 Berlin, Germany., Jaouen F; ICGM, Univ. Montpellier, CNRS, ENSCM, 34293 Montpellier, France., Root TW; Department of Chemical and Biomolecular Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States., Stahl SS; Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
Jazyk: angličtina
Zdroj: Journal of the American Chemical Society [J Am Chem Soc] 2023 Dec 06; Vol. 145 (48), pp. 26222-26237. Date of Electronic Publication: 2023 Nov 20.
DOI: 10.1021/jacs.3c08790
Abstrakt: Mononuclear Fe ions ligated by nitrogen (FeN x ) dispersed on nitrogen-doped carbon (Fe-N-C) serve as active centers for electrocatalytic O 2 reduction and thermocatalytic aerobic oxidations. Despite their promise as replacements for precious metals in a variety of practical applications, such as fuel cells, the discovery of new Fe-N-C catalysts has relied primarily on empirical approaches. In this context, the development of quantitative structure-reactivity relationships and benchmarking of catalysts prepared by different synthetic routes and by different laboratories would be facilitated by the broader adoption of methods to quantify atomically dispersed FeN x active centers. In this study, we develop a kinetic probe reaction method that uses the aerobic oxidation of a model hydroquinone substrate to quantify the density of FeN x centers in Fe-N-C catalysts. The kinetic method is compared with low-temperature Mössbauer spectroscopy, CO pulse chemisorption, and electrochemical reductive stripping of NO derived from NO 2 - on a suite of Fe-N-C catalysts prepared by diverse routes and featuring either the exclusive presence of Fe as FeN x sites or the coexistence of aggregated Fe species in addition to FeN x . The FeN x site densities derived from the kinetic method correlate well with those obtained from CO pulse chemisorption and Mössbauer spectroscopy. The broad survey of Fe-N-C materials also reveals the presence of outliers and challenges associated with each site quantification approach. The kinetic method developed here does not require pretreatments that may alter active-site distributions or specialized equipment beyond reaction vessels and standard analytical instrumentation.
Databáze: MEDLINE