@article{Li2025, 
author = {Jiaxin Li and Caiting Sun and Haiyang Fan and Feilong Dong and Zunhang Lv and Rui Liu and Wenxiu Yang and Bo Wang},
title = {Boosting active site accessibility and alleviating mass transfer resistance for high-performance fuel cells},
year = {2025},
journal = {Nano Research},
volume = {18},
number = {8},
pages = {94907654},
keywords = {metal organic frameworks, oxygen reduction reaction, oxygen mass transfer, proton exchange membrane fuel cell, zinc air battery},
url = {https://www.sciopen.com/article/10.26599/NR.2025.94907654},
doi = {10.26599/NR.2025.94907654},
abstract = {Precise engineering of single-atom catalysts (SACs) with hierarchical porous structures and optimized mass/charge transfer properties is crucial for advancing oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). Herein, we present a novel molten salt-assisted pyrolysis strategy that employs a “dimensional reduction and pore creation” approach to exfoliate three-dimensional (3D)-metal–organic frameworks (MOFs) into three-dimensional porous carbon nanosheets doped with single-atom Fe, resulting in Fe SACs supported on hierarchical porous nitrogen-doped carbon (Fe SA@HPNC). The molten salt treatment simultaneously induces exfoliation and etching, resulting in a hierarchical porous structure with both micropores and mesopores, and a remarkably high specific surface area of 919.5 m2·g−1. The two-dimensional nanosheet structure enhances the anchoring of Fe by exposing more surface micropores, which reduces Fe being deeply buried in internal micropores and improves oxygen accessibility and mass/charge transfer efficiency. The Fe SA@HPNC demonstrates excellent ORR performance with a half-wave potential of 0.90 V and a kinetic current density of 19.9 mA·cm−2. When applied as the cathode in PEMFCs, the Fe SA@HPNC-based cell achieves a remarkable maximum power density of 900 mW·cm−2. Distribution of relaxation times analysis further reveals that the exfoliated catalyst exhibits enhanced ORR kinetics and reduced oxygen transport resistance.}
}