Investigation on the demetallation of Fe-N-C for oxygen reduction reaction: The influence of structure and structural evolution of active site

Xu, Xinlong ¹Zhang, Xiaoming ¹Kuang, Zhichong ¹Xia, Zhangxun ¹Rykov, Alexandre, I ¹Yu, Shansheng ²Wang, Junhu ¹Wang, Suli ¹Sun, Gongquan¹

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作者信息

1. Chinese Acad Sci
2. Jilin Univ
折叠

Abstract

Iron-nitrogen-carbon (Fe-N-C) catalysts for oxygen reduction reaction (ORR) are promising candidates in fuel cell devices but the poor stability remains a grave challenge. The elimination of demetallation is pivotal for extending the life but still incapable due to the ambiguous mechanism. Herein, we show that the structure of FeN4 site and its structural evolution during ORR has the significant influence. The end-of-test/in-situ Mossbauer spectroscopy and density functional theory study reveal that D1 mainly contributes to the ORR activity but suffers severe demetallation, which is likely due to the instability of FeN4C8. The faster demetallation during ORR, especially at higher potential, can be attributed to the weaker coordination of FeN4 induced by oxygenated intermediate and electric field according to ab initio molecular dynamics simulations. Finally, the binding energy of Fe-N bond is introduced to describe the influence of structure and structural evolution and give guidance to the improvement of stability.

Key words

Oxygen reduction reaction/Fe-N-C/Stability/Demetallation/Mossbauer spectroscopy/DENSITY-FUNCTIONAL THEORY/CATALYTIC SITES/FE/N/C-CATALYSTS/ELECTRIC-FIELD/IRON/CARBON/ELECTROCATALYSTS/STABILITY/MOSSBAUER/IDENTIFICATION

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出版年

2022

Applied Catalysis

ISSN：0926-3373

被引量21

参考文献量59

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