@article{Li2025, 
author = {Zhiwen Li and Yan Xie and Yangkai Han and Hezhen Wang and Jianxin Gao and Li Chen and Ling Xu and Linguo Lu and Yun Zhao and Erdong Wang and Gao Li},
title = {Unraveling the significance of FeN4 and Fe3S4 active species for sustained direct ammonia fuel cells and zinc-air batteries},
year = {2025},
journal = {Nano Research Energy},
volume = {4},
pages = {e9120169},
keywords = {Fe3S4, FeN4, oxygen reduction reaction, direct ammonia fuel cells, Zn-air batteries},
url = {https://www.sciopen.com/article/10.26599/NRE.2025.9120169},
doi = {10.26599/NRE.2025.9120169},
abstract = {Transition metal electrocatalysts are deem to be alternatives for the replacement of commercial Pt/C as highly efficient oxygen reduction reaction (ORR) electrocatalysts in the applications of advanced energy conversion/storage technologies. Herein, we reprecipitate hemin on polypyrrole (PPy) modified carbon materials (R-Hm/PPy@C), which boosts up the ORR performances. A high half-wave potential (E1/2) of 0.896 V (vs. RHE) and kinetic current density (JK) of 40.9 mA·cm−2 at 0.80 V (vs. RHE) of R-Hm/PPy@C outperforms these of commercial Pt/C in a 0.1 M KOH electrolyte. Moreover, the direct ammonia fuel cells (DAFC) and zinc-air batteries (ZAB) assembled by R-Hm/PPy@C deliver remarkable peak power densities of 288.4 mW·cm−2 in an electrolyte containing 3 M NH3 and 3 M KOH, and 180.2 mW·cm−2 with a high capacity of 820 mAh·gcat.−1 in a 6 M KOH solution. Such superior electrocatalytic performances are not only due to the synergistic effect of Fe3S4 particles and FeN4 single sites, but also are improved by enriched N-doped C species, further corroborated by theoretical calculations. Overall, this study delivers an efficacious approach to fabricate non-noble metal electrocatalysts (NNMEs) by engineering the synergistic effect of nanoparticles (NPs) and single-atom species with N-enriched dopants towards elevated electrocatalytic activities for energy conversion/storage devices.}
}