Breaking the Linear Scaling Relations for the Oxygen Reduction Reaction with a Dual-Atom Catalyst Composed of a MnFe-Porphyrrole Aerogel
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Breaking the Linear Scaling Relations for the Oxygen Reduction Reaction with a Dual-Atom Catalyst Composed of a MnFe-Porphyrrole Aerogel.pdf (2.12 MB)
Authors
0009-0007-2383-332X Date
2025
Journal Title
Journal ISSN
Volume Title
Publisher
Wiley-VCH GmbH
Abstract
Bimetallic catalysts offer enhanced catalytic performance through synergistic interactions between the two metals, allowing them to break the linear scaling relations and reach high electrocatalytic activity. This study presents bimetallic aerogel-based catalyst synthesized as a covalent, three-dimensional framework containing neighboring iron and manganese sites. The aerogel structure provides a high surface area and porosity, facilitating an ultra-high active site density and efficient mass transport. The MnFe porphyrrole's unique structure is obtained by alternately linking Mn-porphyrin and Fe-corrole complexes. It exhibited outstanding performance with an onset potential of 0.99 VRHE. Comparative studies with a free-base Fe porphyrrole catalyst (Eonset 0.97 VRHE) revealed that while Mn incorporation led to only a slight improvement in half-cell performance, it resulted in significantly enhanced performance in anion exchange membrane fuel cell. The MnFe catalyst achieved an OCV of 0.97 V and a peak power density of 0.27 W cm−2, outperforming the free-base Fe counterpart. Using density functional theory calculations, we show that the higher ORR activity of MnFe-porphyrrole is due to charge transfer between Mn and Fe atoms, which is absent in the reference free-base Fe-porphyrrole. These findings underscore the advantages of bimetallic catalysts in improving ORR activity and fuel cell efficiency by leveraging synergistic effects. Graphical Abstract A bioinspired MnFe porphyrrole aerogel catalyst is synthesized using a covalent 3D framework with adjacent metal centers. The bimetallic structure enhances ORR activity through Mn─Fe synergy and high active site density. Fuel cell tests show over a 30% increase in peak power density, with DFT calculations confirming metal–metal charge transfer as the source of improved performance.
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Early View - Online Version of Record before inclusion in an issue.
Citation
Angew. Chem. Int. Ed. 2025, e202514013 (1 of 8) // https://doi.org/10.1002/anie.202514013