Carbon-Vacancy-Induced Fe Coordination Modulation in FeZn Dual-Atom Sites for Enhanced Bifunctional Oxygen Electrocatalysis.

Bai, Yu; Chen, Yingbi; Wang, Yuchao; Yang, Peiyao; Zheng, Haitao; Wang, Meng; Liu, Wei; Fang, Guozhao et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

Precisely modulating the coordination structure of neighboring metal atomic sites is urgently required yet remains technically challenging. Herein, we report a carbon-vacancy-induced Fe coordination environment modulation in FeZn dual-atom sites (FeZnN<sub>6</sub>-V<sub>C</sub>) to boost bifunctional oxygen electrocatalysis. Finite element simulation and electronic structure characterization reveal that carbon vacancies promote electron transfer from Fe-N<sub>4</sub> to neighboring Zn-N<sub>4</sub> sites, establishing favorable electronic interactions. In situ Raman spectroscopy further identifies the key O-O<sup>-</sup> intermediate (corresponding to OOH*) and the FeOOH active phase during oxygen evolution reaction (OER), both showing significantly lowered onset potentials. Compared with conventional FeZn dual-atom catalysts, FeZnN<sub>6</sub>-V<sub>C</sub> achieves a 174 mV decrease in OER overpotential at 10 mA cm<sup>-2</sup> and exhibits improved oxygen reduction reaction performance in alkaline media. The corresponding quasi-solid-state Zn-air battery delivers a long cycling life of 82.3 h at 50 mA cm<sup>-2</sup>. This work offers a versatile carbon-vacancy strategy to tune the local coordination of dual-atomic sites for advanced electrocatalysis.