Articles & Issues
- Language
- English
- Conflict of Interest
- In relation to this article, we declare that there is no conflict of interest.
- Publication history
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Received February 28, 2025
Revised May 3, 2025
Accepted May 28, 2025
Available online December 25, 2025
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This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits
unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
All issues
Enhancing Active Site Density in Fe–NC Electrocatalysts via 2D Structural Engineering for Efficient Oxygen Reduction
https://doi.org/10.1007/s11814-025-00488-z
Abstract
Enhancing the active site density of metal–nitrogen–carbon (M–NC) catalysts is critical for improving their oxygen reduction
reaction (ORR) performance in proton exchange membrane fuel cells (PEMFCs). In this study, we report a two-dimensional
(2D) Fe–NC sheet catalyst designed to maximize active site exposure through structural engineering. Unlike conventional
three-dimensional (3D) Fe–NC catalysts, the 2D Fe–NC sheet exhibits a significantly higher surface area and increased
Fe–N4 site density, leading to enhanced ORR kinetics. The expanded electrochemical interface and improved active site
accessibility contribute to superior site utilization and mass transport properties. Electrochemical evaluations confirm that
the 2D Fe–NC sheet outperforms its 3D counterpart in ORR activity, demonstrating higher half-wave potential and turnover
frequency. Furthermore, PEMFC single-cell tests reveal that the 2D Fe–NC sheet achieves comparable performance to
previously reported M–NC catalysts, particularly when combined with 3D structures to mitigate aggregation effects. This
study highlights the importance of morphology engineering in optimizing M–NC catalysts for efficient PEMFC applications.

