@article{Sun2026, 
author = {Hongmin Sun and Ziliang Deng and Jingbo Li and Shuailong Zhang and Mufan Li and Haibo Jin and Zipeng Zhao},
title = {Low-porosity carbon templates mitigate mass transport limitations in Fe-N-C catalysts},
year = {2026},
journal = {Nano Research},
volume = {19},
number = {1},
pages = {94908227},
keywords = {oxygen reduction reaction, mass transport, fuel cell, Fe-N-C catalysts, low-porosity carbon template, surface-exposed atomic sites},
url = {https://www.sciopen.com/article/10.26599/NR.2025.94908227},
doi = {10.26599/NR.2025.94908227},
abstract = {Fe-N-C catalysts, as promising non-precious metal alternatives for the oxygen reduction reaction (ORR), still suffer from severe mass transport limitations in proton exchange membrane fuel cells (PEMFCs) due to water flooding of active sites embedded in micropores. Although pore engineering through a selected template is a general strategy, the structural features of an ideal template, particularly those governing the exposure of active sites and thus affecting mass transport, remain elusive. Here, we demonstrate that low-porosity carbon templates maximize the ratio of active sites distributed at or near the surface, thereby enhancing their exposure and accessibility while reducing mass transport resistance during the ORR process. The Clp-1@PPy and Clp-2@PPy (PPy = polypyrrole) catalysts, derived from low-porosity carbon templates, achieve peak power densities of 0.96 and 1.03 W·cm−2 under H2/O2 and 0.50 and 0.52 W·cm−2 under H2/air, demonstrating excellent performance in PEMFC tests. Structural and electrochemical characterizations reveal that the enhanced surface exposure of active sites effectively mitigates mass transport resistance during the ORR, thereby offering a general design principle for overcoming mass transport limitations in Fe-N-C catalysts for PEMFC applications.}
}