Engineering the Lewis Acidity of Fe Single-Atom Sites via Atomic-Level Tuning of Spatial Coordination Configuration for Enhanced Oxygen Reduction.

作者：Qingyun Qu, Yu Mao, Shu-Fang Ji, Jiangwen Liao, Juncai Dong, Li-Gang Wang, Qichen Wang, Xiao Liang, Ze-Dong Zhang, Jia-Rui Yang, Hai-Jing Li, Yongfang Zhou, Zi-Yun Wang, Geoffrey I. N. Waterhouse, Dingsheng Wang, Yadong Li · 发表于：Journal of the American Chemical Society · 年份：2025 · DOI：10.1021/jacs.4c17444 · 被引用次数：141 · 研究领域：Medicine

Nitrogen-doped carbon-supported Fe catalysts (Fe-N-C) with Fe-N4 active sites hold great promise for the oxygen reduction reaction (ORR). However, fine-tuning the structure of Fe-N4 active sites to enhance their performance remains a grand challenge. Herein, we report an innovative design strategy to promote the ORR activity and kinetics of Fe-N4 sites by engineering their Lewis acidity, which is achieved by tuning the spatial Fe coordination geometry. Theoretical calculations indicated that Fe1-N4SO2 sites (with an axial -SO2 group bonded to Fe) offered favorable Lewis acidity for the ORR, leading to optimized adsorption energies for the key ORR intermediates. To implement this strategy, we developed a molecular-cage-encapsulated coordination strategy to synthesize a Fe single-atom site catalyst (SAC) with Fe1-N4SO2 sites. In agreement with theory, the Fe1-N4SO2/NC catalyst demonstrated outstanding ORR performance in both alkaline (E1/2 = 0.910 V in 0.1 M KOH) and acidic media (E1/2 = 0.772 V in 0.1 M HClO4), surpassing commercial Pt/C and traditional Fe SACs with Fe1-N4 sites or planar S-coordinated Fe1-N4-S sites. Moreover, this newly developed catalyst showed great application potential in quasi-solid-state Zn-air batteries, delivering superior performance across a wide temperature range.