TY - JOUR
T1 - Unravelling the Stability Stressors of Atomically Dispersed Fe-N-C Oxygen Reduction Catalysts
AU - Xie, Xiaohong
AU - Li, Boyang
AU - Xu, Pan
AU - Sougrati, Moulay Tahar
AU - Garcia-Serres, Ricardo
AU - Cullen, David A.
AU - Kropf, A. Jeremy
AU - Xia, Fan
AU - Song, Miao
AU - Saha, Sulay
AU - Zeng, Yachao
AU - Engelhard, Mark H.
AU - Bowden, Mark E.
AU - Zhang, Hanguang
AU - Yan, Litao
AU - Lemmon, Teresa
AU - Li, Xiaohong S.
AU - Martinez, Ulises
AU - Cheng, Yingwen
AU - Wu, Gang
AU - Zelenay, Piotr
AU - Ramani, Vijay
AU - Myers, Deborah J.
AU - Jaouen, Frédéric
AU - Yang, Lijun
AU - Wang, Guofeng
AU - Shao, Yuyan
PY - 2025/12/31
Y1 - 2025/12/31
N2 - Enhancing the catalytic stability of Fe-N-C catalysts for cathodic oxygen reduction in proton-exchange membrane fuel cells (PEMFCs) necessitates an in-depth understanding of their degradation mechanisms. This study identifies key stressors affecting the stability of Fe-N-C catalysts, specifically acidic environment, oxygen (O2), and reactive oxygen species (ROS). Through ex situ/operando experiments, we show that the oxidation of local carbon by acidic environment + O2 + ROS, along with the demetalation of catalytic FeNxCy sites by O2 or O2 + ROS, is the primary factor responsible for the initial fast degradation of Fe-N-C catalysts. The demetalation of FeNxCy sites, influenced by O2, in particular by O2 + ROS, leads to the subsequent gradual degradation of Fe-N-C. Notably, FeN4C12-type active sites are more susceptible to demetalation than FeN4C10-type sites in O2 or O2 + ROS. Our findings indicate that, besides constructing more stable FeNxCy sites, preventing local carbon oxidation and scavenging of ROS are all critical for maintaining the stability of Fe-N-C catalysts.
AB - Enhancing the catalytic stability of Fe-N-C catalysts for cathodic oxygen reduction in proton-exchange membrane fuel cells (PEMFCs) necessitates an in-depth understanding of their degradation mechanisms. This study identifies key stressors affecting the stability of Fe-N-C catalysts, specifically acidic environment, oxygen (O2), and reactive oxygen species (ROS). Through ex situ/operando experiments, we show that the oxidation of local carbon by acidic environment + O2 + ROS, along with the demetalation of catalytic FeNxCy sites by O2 or O2 + ROS, is the primary factor responsible for the initial fast degradation of Fe-N-C catalysts. The demetalation of FeNxCy sites, influenced by O2, in particular by O2 + ROS, leads to the subsequent gradual degradation of Fe-N-C. Notably, FeN4C12-type active sites are more susceptible to demetalation than FeN4C10-type sites in O2 or O2 + ROS. Our findings indicate that, besides constructing more stable FeNxCy sites, preventing local carbon oxidation and scavenging of ROS are all critical for maintaining the stability of Fe-N-C catalysts.
UR - https://www.scopus.com/pages/publications/105026454059
U2 - 10.1021/jacs.5c15451
DO - 10.1021/jacs.5c15451
M3 - Article
C2 - 41400425
AN - SCOPUS:105026454059
SN - 0002-7863
VL - 147
SP - 48117
EP - 48126
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 52
ER -