@article{Liu2025, 
author = {Xinyu Liu and Wanlin Zhou and Yuhao Zhang and Qizheng An and Jingjing Jiang and Youcai Che and Xupeng Qin and Haixin Sun and Qinghua Liu and Shiqiang Wei},
title = {Engineering the first coordination sphere of FeN4 sites with less electronegative heteroatoms for oxygen reduction catalysis},
year = {2025},
journal = {Nano Research},
volume = {18},
number = {12},
pages = {94907768},
keywords = {oxygen reduction reaction, doping, asymmetrical configuration, single-atom sites},
url = {https://www.sciopen.com/article/10.26599/NR.2025.94907768},
doi = {10.26599/NR.2025.94907768},
abstract = {Rational modulation of Fe-N4 coordination symmetry through heteroatom doping with distinct electronegativities has emerged as a promising strategy to optimize the performance of the oxygen reduction reaction (ORR). Here, we systematically investigate the less electronegative sulfur- and phosphorus-doped Fe single-atom catalysts and demonstrate that the S-doped catalyst (Fe-SNC) achieves superior ORR activity (E1/2 = 0.904 V vs. RHE), surpassing both the P-doped Fe-PNC and the undoped Fe-NC control samples, while maintaining exceptional durability. Synchrotron radiation X-ray absorption spectroscopy verified the precise engineering of the asymmetric Fe-S1N3 and Fe-P1N3 configurations within the ZIF-8-derived carbon matrices, confirming successful manipulation of the first coordination sphere. In situ synchrotron radiation infrared spectroscopy further elucidates accelerated *OOH dissociation kinetics in Fe-SNC, which benefits from the optimization of the electronic structure of Fe 3d by S doping. These findings conclusively establish geometric symmetry breaking via electronegativity-driven electronic modulation as an effective strategy for advancing metal-N4 catalyst design.}
}